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Rationally constructing functionalized cocatalysts for removing chemically inert polychlorinated biphenyls is significant and challenging. In this study, we have synthesized uniform Pd nanocrystals (Pd NCs) with cube (CUB) and octahedron (OCT) geometries, corresponding to the exposed (100) and (111) facets, and they were incorporated with ultrathin TiO2(B) nanosheets (TBs) for the photocatalytic dechlorination of polychlorinated biphenyls under visible light illumination (λ ≥ 400 nm). Photocatalytic performance experiments revealed that CUB/TBs is more efficient with a 200% enhancement higher than OCT/TBs. Physicochemical characterizations reveal that the CUB possesses higher surface charge density than OCT, which promotes the activation of the C–Cl bond of polychlorinated biphenyls, leading to higher dechlorination performances of CUB/TBs than OCT/TBs. This study not only fundamentally elucidates the effect of facet-engineering palladium nanocrystals on the photocatalytic dechlorination of polychlorinated biphenyls, but also paves the way for rationally fabricating superior photocatalysts for other advanced applications.

Two-component composites consisting of transition metal copper oxide (CuO) and graphite carbon nitride (g-C3N4) were successfully synthesized. This CuO/g-C3N4 displays a high reversible specific capacity (1530.4 F g−1, 2 A g−1) as an anode material.

The quaternary tungstates Li3Ba2RE3(WO4)8 (RE = La–Nd, Sm–Ho) were obtained by a ceramic synthesis route and were characterized by powder and single crystal X-ray diffraction. The structures of Li3Ba2Pr3(WO4)8 and Li3Ba2Tb3(WO4)8 were refined from single crystal diffractometer data: RbLiBi2(MoO4)4 type, space group C2/c, a = 528.57(2), b = 1292.39(6), c = 1934.80(10) pm, β = 91.522(4)°, 2151 F2 values, 108 parameters for Li3Ba2Pr3(WO4)8 and a = 520.54(2), b = 1272.03(6), c = 1918.85(10) pm, β = 91.948(4)°, 2020 F2 values, 108 variables for Li3Ba2Tb3(WO4)8. Striking polyhedral building units in these tungstates are WO4 tetrahedra and LiO6 octahedra, while the mixed occupied site and the barium atoms have higher coordination numbers, i.e. RE/Li@O8 and Ba@O10. In addition to the powder quality assessment by means of reflection spectroscopy, the synthesized samples were studied for their suitability as a scintillator material. Therefore, X-ray excited luminescence measurements where performed. Apart from Li3Ba2Ce3(WO4)8 and Li3Ba2Nd3(WO4)8, all compounds show strong emission under X-ray irradiation. Li3Ba2La3(WO4)8 and Li3Ba2Gd3(WO4)8 show blue CT luminescence caused by tungstate units, while the other samples show typical and multiple lines due to well known [Xe]4fn → [Xe]4fn transitions.

C-term magnetic circular dichroism (MCD) spectroscopy is a powerful method for probing d–d and f–f transitions in paramagnetic metal complexes. However, this technique remains underdeveloped both experimentally and theoretically for studies of U(V) complexes of Oh symmetry, which have been of longstanding interest for probing electronic structure, bonding, and covalency in 5f systems. In this study, C-term NIR MCD of the Laporte forbidden f–f transitions of [UCl6]− and [UF6]− are reported, demonstrating the significant fine structure resolution possible with this technique including for the low energy Γ7 → Γ8 transitions in [UF6]−. The experimental NIR MCD studies were further extended to [U(OC6F5)6]−, [U(CH2SiMe3)6]−, and [U(NC(tBu)(Ph))6]− to evaluate the effects of ligand-type on the f–f MCD fine structure features. Theoretical calculations were conducted to determine the Laporte forbidden f–f transitions and their MCD intensity experimentally observed in the NIR spectra of the U(V) hexahalide complexes, via the inclusion of vibronic coupling, to better understand the underlying spectral fine structure features for these complexes. These spectra and simulations provide an important platform for the application of MCD spectroscopy to this widely studied class of U(V) complexes and identify areas for continued theoretical development.

In halogenoantimonate(III) and halogenobismuthate(III) organic–inorganic hybrids, chains of trans-connected octahedra, trans-[MX5]∞, are considered attractive anionic structures for inducing ferroelectricity. The latter is realized by displacing the bridging halogen atoms along the chain direction – the process that changes the polarity of the whole unit. Advances in the identification of such materials have been hindered, however, by substantial difficulty in obtaining such structures. Here we investigate structural and dielectric properties of three families of compounds based on 2-mercaptopyrimidinium, 2-aminopyrimidinium, and 2-amino-4-methylpyrimidinium cations in which 8 out of 12 compounds show trans-[MX5]∞ chains in their crystal structures. Two of the compounds adopt a polar P21 space group and are potentially ferroelectric. We perform a detailed structural analysis of all compounds with trans-[MX5]∞ chains discovered by far to understand the factors that lead to the chains' formation. We reveal that the size of a cation predominantly defines the accessibility of structures with this anionic form and we provide rules for designing hybrids with trans-[MX5]∞ chains to help guide future efforts to engineer materials with interesting non-linear electrical properties.

Seven isostructural heterometallic luminescent (Ir,Cd) coordination polymers were prepared upon the combination of tris-chelate cationic Ir(III) complexes behaving as metalloligands with Cd(II) salts. Three octahedral Ir(III) complexes have been considered in the present report. They consist of a bipyridine unit functionalised with 3-pyridyl moieties as peripheral coordinating sites and two 2-phenylpyridyl cyclometalating derivatives. Three cadmium halide salts CdX2 (X = Cl, Br, I) were used and rearranged themselves during the self-assembly process with the metallatectons to afford a dianonic trinuclear Cd node [Cd3X8]2-. Seven out of the nine possible metallotecton-metal salt combinations could be characterised in the crystalline phase by X-ray diffraction on single crystals proving the isostructurality of the seven extended architectures studied. All of the CPs are luminescent with small shifts observed in the emission wavelength compared to the discrete complexes. Depending on the degree of fluorination of the two cyclometalating units, tuning of the emission wavelength of the discrete complexes as well as of the resulting coordination polymers is achieved.

Two new CeIV/O2− clusters, (pyH)8[Ce10O4(OH)4(O3PPh)12(NO3)12] (1) and [Ce6O4(OH)4(O2PPh2)4(O2CtBu)8] (2), have been prepared that contain P-based ligands for the first time. They were obtained from the reaction of (NH4)2[Ce(NO3)6], PhPO3H2 or Ph2PO2H, and tBuCO2H in a 2 : 1 : 2 molar ratio in pyridine/MeOH (10 : 1 mL). Both compounds contain a {Ce6O4(OH)4} face-capped octahedral core, with 1 containing an additional four CeIV on the outside to give a supertetrahedral Ce10 topology; the {Ce6O8} unit is the smallest recognizable fragment of the fluorite structure of CeO2. The HO˙ radical scavenging activities of 1 and 2 were measured by UV/vis spectral monitoring of methylene blue oxidation by HO˙ radicals in the presence and absence of the Ce/O clusters, and the results compared with those for larger Ce24 and Ce38 molecular nanoparticles of CeO2 prepared in previous work. 1 and 2 are both very poor HO˙ radical scavengers compared with Ce24 and Ce38, a result that is consistent with reports in the literature that PO43− ions inhibit the radical scavenging ability of traditional CeO2 nanoparticles and putatively assigned to PO43− binding to the surface.

An exploratory study of the lead-tellurium-oxygen phase space led to two new compounds, Ba3PbTe6O16 (BPTO) and Na2Pb9(μ6-O)2(Te2O10)2 (NPTO), which were synthesized under hydrothermal conditions at 550 °C and 210 °C, respectively, and characterized by single-crystal X-ray diffraction, infrared and X-ray photoelectron spectroscopy. BPTO adopts a layer structure. The Te4+ cation in BPTO is bonded to four oxygen atoms at about 2.0 A with two more oxygens at about 3.0 A. The seesaw-shaped TeO4 units share corners to form 2D layers containing six-membered rings and the Ba2+ and Pb2+ cations are situated in the interlayer region. The structure of NPTO contains dimers of edge-sharing Te6+O6 octahedra, which are connected through five-coordinate Pb2+ cations. A unique six-coordinate O atom is at the center of the octahedron formed by five Pb2+ and one Na+ cations. BPTO is one of the few metal tellurites which were synthesized under supercritical hydrothermal reaction conditions. The Pb2+ cation in NPTO shows pronounced stereochemical effects of the lone electron pair. In contrast, BPTO shows no stereochemical evidence of the inert pair.

Perovskite solar devices are nowadays the fastest advancing photovoltaic technology. Their large-scale application is however restrained by instability and toxicity issues. Alloying is a promising way to stabilize perovskites, optimizing at the same time their absorption and charge-transport properties. We perform an extensive computational study of the thermodynamic stability and electronic properties of oxynitride, oxyfluoride and nitrofluoride perovskites. We consider quaternary stoichiometries of the type ABX2Y, where A and B are any elements of the periodic table and X and Y are nitrogen, oxygen, or fluorine. As a starting point we explore the composition space using a simple five-atom perovskite unit cell. We then filter the candidate compositions according to their distance to the convex hull of thermodynamic stability. For the most stable systems, we then investigate other prototype structures, including more complex perovskite phases that allow for octahedral distortions, and a few non-perovskite geometries. Furthermore, for some paradigmatic cases, we study the effect of disorder by exhaustive enumeration of all possible disordered stoichiometric phases with up to 20 atoms in the unit cell. Our calculations are in very good agreement with data for experimentally known mixed anionic compounds, and predict a series of novel stable (perovskite and non-perovskite) oxynitride and oxyfluoride phases, including some with unexpected chemical composition, and one single nitrofluoride compound. Finally, we calculate and discuss the electronic properties of these compounds and their potential for application as photovoltaic absorbers.

This study reports four SMMs based on silanolate or stannanolate ligands cis-[Dy(OSiPh3)2(THF)4][BPh4]·THF·C6H6 (1), cis-[Dy(OSnPh3)2(THF)4][BPh4]·THF·C6H6·C6H14 (2), fac-[Dy(OSiPh3)3(THF)3]·THF (3) and fac-[Dy(OSiPh3)3(bipy)(THF)]·THF (4).

Stable crystalline complexes of Co(II) acetylacetonate [Co(II)(acac)2], trifluoacetylacetonate [Co(II)(tfac)2] and hexafluoroacetylacetonate [Co(II)(hfac)2] with triphenodioxazines (TPDOs) were synthesized and their structures studied using X-ray crystallography. In the crystal, complexes [Co(II)(tfac)2]TPDO and [Co(II)(hfac)2]TPDO form infinite ⋯N⋯Co⋯N⋯ chains featuring 1D coordination polymeric structures, whereas in the [Co(II)(acac)2]TPDO complex, the Co(acac)2 units fill only half of the possible crystallographic positions. The electron accepting trifluoro substituents in the diketonate moieties significantly enhance the thermal stability of the complexes with TPDO. Of all the complexes, only [Co(II)(hfac)2]TPDO does not dissociate into the components in solution. In all studied complexes, the Co(II) atom is in a high-spin state and has distorted octahedral surroundings. Distortion of the octahedral polyhedrons appears as axial stretching of the octahedrons along the Co–N bonds; it is due to the specific features of the crystalline structure of the metal polymeric chain in the compounds.

A new series of cyanido-bridged {FeIIILnIII} heterobimetallic chains of general formula {[(NC)FeIII{HB(pz)3}(μ-CN)2LnIII(bpdo)(NO3)2(H2O)]·CH3CN}n [HB(pz)3− = hydrotris(pyrazol-1-yl)borate, bpdo = 2,2′-bipyridine-N,N′-dioxide and Ln = Gd (1), Tb (2), Dy (3) and Ho (4)], were obtained by using the low-spin [Fe{HB(pz)3}(CN)3]− complex as a metalloligand towards the preformed [Ln(bdpo)(NO3)2(H2O)]+ species. Single-crystal X-ray diffraction shows that 1–4 are isostructural compounds that crystallize in the monoclinic P21/c space group. Their crystal structure consists of neutral 1D coordination polymers where the [Fe{HB(pz)3}(CN)3]− fragment adopts a bis-monodentate coordination mode, through two cis-cyanido ligands, towards two [Ln(bdpo)(NO3)2(H2O)]+ units. The two cis-oriented cyanide bridges determine the formation of angular cyanido-bridged [FeIIILn2III] trinuclear moieties that are alternatively perpendicular to each other, describing a unique zig-zag chain. Each crystallographic independent iron(III) ion in 1–4 is six-coordinate in a distorted octahedral surrounding, the coordination sphere being built by one tridentate HB(pz)3− ligand and three cyanide groups, disposed in a fac-arrangement. The lanthanide(III) ions from 1–4 are nine-coordinate in an environment close to a distorted muffin-like geometry (Cs symmetry) and a spherical tricapped trigonal prism (D3h symmetry). The iron⋯lanthanide intermetallic distances through the cyanide ligands are 5.36/5.50 (1), 5.49/5.35 (2), 5.34/5.48 (3) and 5.33/5.47 A (4). Two-dimensional supramolecular networks are built from the heterobimetallic d/f chains through weak slipped-off π–π and C–H⋯π stacking interactions. Solid-state direct-current (dc) magnetic susceptibility measurements in the temperature range 1.9–300 K for 1–4 revealed the occurrence of weak antiferromagnetic interactions in 1 [J = −0.298 cm−1 (α = 0), the spin Hamiltonian being defined as with SA = 1/2 and SB = 7/2] whereas the coexistence of the spin–orbit coupling of the lanthanide(III) [TbIII (2), DyIII (3), HoIII (4)] and low-spin iron(III) ions together with the ligand field effects masked the visualization of the possible magnetic interactions in 2–4.

Rutile GeO2 with d10 metal in octahedral coordination possesses both a high charge separation rate and carrier mobility because the partial charge density is dominated by Ge-O anti-bonding for CBM. GeO2 is capable of photocatalytic water splitting, even visible light water splitting through combination with the sensitizer melon.

Ultrathin nanosheets of luminescent metal-organic frameworks or coordination polymers have been widely used for sensing ions, solvents and biomolecules but, as far as we are aware, not yet used for temperature sensing. Herein we report two luminescent uranyl phosphonates based on 2-(phosphonomethyl)benzoic acid (2-pmbH3), namely (UO2)(2-pmbH2)2 (1) and (H3O)[(UO2)2(2-pmb)(2-pmbH)] (2). The former has a supramolecular layer structure, composed of chains of corner-sharing {UO6} octahedra and {PO3C} tetrahedra which are connected by hydrogen bonds between phosphonate and carboxylic groups. Compound 2 possesses a unique 2D anionic framework structure, where the inorganic uranyl phosphonate chains made up of {UO7} and {PO3C} polyhedra are cross-linked by 2-pmb3- ligands. The carboxylic groups of 2-pmbH2- ligands are pendant on the two sides of the layers and form hydrogen bonds between the layers. Both compounds can be exfoliated in acetone via a top-down freeze-thaw method, resulting in nanosheets of two-layer thickness. Interestingly, the photoluminescence (PL) of 1 and 2 is highly temperature sensitive. Variable temperature PL studies revealed that compounds 1 and 2 can be used as thermometers in the temperature ranges 120-300 K and 100-280 K, respectively. By doping the nanosheets into polymer matrix, 1-ns@PMMA and 2-ns@PMMA were prepared. The PL intensity of 1-ns@PMMA is insensitive to temperature, unlike that of the bulk sample. While 2-ns@PMMA exhibits similar temperature-dependent luminescence behaviour to its bulk counterpart, thereby enabling its potential application as a thermometer in the temperature range 100-280 K.

Sluggish charge transfer is the major problem which restricts the development of metal–organic framework (MOF)-based photocatalysts. Recently, facet-engineering has been proven to be an effective method for solving this issue. However, due to difficulties in regulating the exposed facets of MOFs, there are few reports about the facet-engineering of MOF-based photocatalysts. Here, we firstly report facet-engineering for promoting the photocatalytic activity of NH2-UiO-66 crystals. In this study, by regulating the influence of kinetics and thermodynamics, cubic, tetra-decahedral, and octahedral forms of NH2-UiO-66 are synthesized. The photocatalytic hydrogen evolution rate of tetra-decahedral NH2-UiO-66 with co-exposed (100) and (111) crystal facets reaches 64.06 μmol g−1 h−1, which is approximately 2 and 1.5 times greater than that of the cubic and octahedral forms of NH2-UiO-66, respectively. The density functional theory (DFT) calculation and ultrafast spectroscopy results indicate that a slight staggering exists in the band structure of (100) and (111) facets, causing the facets junction to appear. The facet junction promotes the charge separation efficiency and prolongs the lifetime of the charge carriers, thereby giving tetra-decahedral NH2-UiO-66 optimal photocatalytic performance. This study demonstrates the feasibility and potential of facet-engineering for photocatalytic applications of MOFs.

The catalytic decomposition of N2O was investigated over Mg–Co composite oxide catalysts. It was found that the activities of the catalysts could be significantly enhanced by hydrothermally treating the precipitate coming from the co-deposition of Mg2+ and Co2+ using Na2CO3 as a precipitant. By correlating the physical and chemical characterization results with the activities for the catalyst samples prepared with and without the hydrothermal treatment, a mechanism accounting for the increased activity due to the hydrothermal treatment was discussed. It was demonstrated that the substitution extent of CoT (tetrahedral cobalt of the spinel) by Mg is the key factor that determines the activity of the composite catalysts, and hydrothermal treatment is highly favorable for the ions' replacement during the preparation procedure. The formation of the coordinatively unsaturated octahedral cobalt (CoO) on the spinel surface is therefore remarkably accelerated under the reaction conditions, since the CoO–O bond is significantly weakened by the substitution, which explains why the hydrothermal treatment gave the resulting catalyst with a much higher activity compared with that without the treatment.

Zeolitic octahedral metal oxides (ZOMOs) are fully inorganic crystalline materials, mostly containing transition metals, and possess a defined framework as well as regular hollow channels. Therefore, they have significant application potential in many fields, particularly catalysis. Herein, we report the synthesis and characterization of zeolitic octahedral niobium oxides (ZOMO-NbOx) and the framework was made of {NbOx} polyhedra ({NbO6} octahedron and {Nb6O27} pentagon units). Microchannels consisting of 7-membered rings with ∼0.4 nm diameter were realized, and rarely reported plural {Nb6O27} units including dimers, trimers, and tetramers were discovered. Owing to the continuous hollow microporous structure that provides a large surface area as well as a shortened transfer path for charge carriers from bulk to the surface, considerably enhanced activities beyond pristine Nb2O5 were achieved towards photocatalytic H2 evolution from (saline) water. The results show a practical case of solo-Nb-based zeolitic materials, which expand the ZOMO family and provide further insights into the design and synthesis of efficient zeolitic semiconductors for artificial photocatalysis.

Organolead halide crystalline materials are an emerging class of high-performance photocatalysts. However, limited studies have been performed to tune their photoactive properties by precise introduction of transition metals. Herein, we report the successful incorporation of four different transition metal centers (Mn2+, Co2+, Ni2+ and Zn2+) into a lead oxyhalide crystalline matrix via isoreticular synthesis. Importantly, the precise control of the incoming transition metal positions has been achieved by its octahedral coordination with three organic ligands. Among them, the Zn2+-incorporated material exhibits the highest catalytic activity and recyclable activity in benzylamine oxidation under UV light, which is probably ascribed to the long carrier lifetime and efficient carrier transfer.

This paper reports two closely related heteropentanuclear manganese complexes, namely, {Na2Mn3(opch)3(μ4-O)(μ2-N3) (μ2-AcO)(μ2-MeO)}·6CH3OH·0.5H2O (1) and {Na2Mn3(opch)3(μ4-O)(μ2-N3)2(μ2-AcO)}·2.5CH3OH·2H2O (2), where H2opch is (E)-N′-(2-hydroxy-3-methoxybenzylidene)pyrazine-2-carbohydrazide. Single-crystal X-ray diffraction analysis reveals that the trigonal bipyramidal skeletons in both complexes are comparable, where a perfect triangular Mn3 motif occupies the equatorial plane. Magnetic investigations suggest that overall antiferromagnetic coupling is present within the triangles of 1 and 2. However, their dynamic magnetic properties are drastically distinct. Indeed, complexes 1 and 2 show two kinds of dual slow magnetic relaxation processes that correspond to anisotropy barriers (Δ) of 9.2 cm−1 (11.4 cm−1 for 2) and 12.8 cm−1 (30.0 cm−1 for 2) for the low- and high-frequency domains, respectively. More importantly, a further comparative study of the structure and magnetism indicates that the coordination sphere of these two model complexes with the homologous hydrazone-based coordination sites undergoes an alteration from methoxide-O to azide-N upon a subtle change of the auxiliary anion accompanied by modulating octahedron geometries, leading to a further influence on different relaxation dynamics.

We report the first homoleptic alkynyl-protected AgCu superatomic nanocluster [Ag9Cu6(tBuCC)12]+ (NC 1, also Ag9Cu6 in short), which has a body-centered-cubic structure with a Ag1@Ag8@Cu6 metal core. Such a configuration is reminiscent of the reported AuAg bimetallic nanocluster [Au1@Ag8@Au6(tBuCC)12]+ (NC 2, also Au7Ag8 in short), which is also synthesized by an anti-galvanic reaction (AGR) approach with a very high yield for the first time in this study. Despite a similar Ag8 cube for both NCs, structural anatomy reveals that there are some subtle differences between NCs 1 and 2. Such differences, plus the different M1 kernel and M6 octahedron, lead to significantly different optical absorbance features for NCs 1 and 2. Density functional theory calculations revealed the LUMO and HOMO energy levels of NCs 1 and 2, where the characteristic absorbance peaks can be correlated with the discrete molecular orbital transitions. Finally, the stability of NCs 1 and 2 at different temperatures, in the presence of an oxidant or Lewis base, was investigated. This study not only enriches the M15+ series, but also sets an example for correlating the structure–property relationship in alkynyl-protected bimetallic superatomic clusters.

Ni-enriched layered materials are utilized as positive electrode materials of high-energy Li-ion batteries. Because electrode reversibility is gradually lost for stoichiometric LiNiO2 after continuous cycles, Ni ions are partially substituted by other metal ions (Co, Mn, Al etc.). However, the origin of deterioration in stoichiometric LiNiO2 is still not fully understand yet. Moreover, the loss of capacities is observed only in the high voltage region (>4.1 V), which is obviously different from the failure mode observed in other electrode materials. Here, we report for the first time the origin of deterioration, which is revealed by an in situ X-ray diffraction study. For fully charged NiO2, Ni ions migrate from original octahedral sites in NiO2 slabs to face-sharing tetrahedral sites in Li layers, by which the O3 to O1 phase transition is suppresed. Note that Ni migration is a reversible process, and the Ni ions migrate back to the original octahedral sites on discharge. However, after continuous cycles, the reversibility of Ni migration is gradually lost, and Ni ions are partially left at the tetrahedral sites in Li layers. Electrode kinetics are also deteriorated because of the Ni occupation in Li layers, and the accumulation of Ni ions at tetrahedral sites results in the loss of reversible capacities in the high voltage region. This finding opens a new way to design high-capacity Ni-enriched electrode materials, leading to the development of high-energy Li-ion batteries.

ErIII complexes are potential candidates for high-performance single molecule magnets (SMMs) just after DyIII. Herein, we thoroughly explore the under-represented class of neutral pseudo-tetrahedral ErIII SMMs and demonstrate their exceptional slow magnetization dynamics. We found that this dynamics is solely controlled by the Raman-like relaxation mechanism in the investigated temperature and frequency range which is an uncommon observation in the field of Ln-based SMMs. We also compare the molecular magnetic memory effect in the form of a waist-restricted magnetic hysteresis loop of the reported pseudo-tetrahedral ErIII SMMs with an example of a hexa-coordinate pseudo-octahedral one, that does not show this effect. Overall, we report four new neutral mononuclear ErIII complexes – three tetra-coordinate: [ErIII(TTBP)3(THF)] (1) (TTBP− = 2,4,6-tri-tert-butyl-phenolate), [ErIII(TTBP)3(TEMPO)] (2) (TEMPO = 2,2,6,6-tetramethylpiperidine 1-oxyl) and [ErIII(BHT)3(THF)] (3) (BHT− = 2,6-di-tert-butyl-4-methylphenolate) and one hexa-coordinate: [Li(THF)2]2[ErIII(N3N)Cl2] complex (4) (N3N = tris(N-trimethylsilyl-2-amidoethyl)amine; [(Me3SiNCH2CH2)3N]3−). Finally, by comparing [ErIII(TTBP)3(THF)] (1) and its radical-functionalized congener [ErIII(TTBP)3(TEMPO)] (2), we show that adding an additional spin on the ligand of an ErIII SMM completely disrupts the slow magnetization dynamics of the parent compound.

The controllable preparation of crystals is a prerequisite for exploring their shape-dependent physicochemical properties. Herein, AgCl crystals with different morphologies including octahedron, trapezohedron (TPH), 12-pod and hexapods with mace pods were successfully prepared by a one-pot synthesis method. In the preparation process, ethylene glycol (EG) was used as a solvent and AgNO3 was used as a precursor of Ag+. In particular, the ionic liquid poly(diallyldimethylammonium chloride) (PDDA) not only acted as a Cl− ion precursor but also as a morphology-controlled stabilizer. We further explored the effects of temperature, ligand and precursor concentration on AgCl crystal growth. Moreover, we investigated the effect of Cl− concentration on the morphology of AgCl by adding different amounts of NaCl. We found that under the condition of the lower concentrations of Cl−, {111}-bound octahedral AgCl crystals will transform into TPH enclosed with the {311} facet as the concentration of Cl− ions increases. However, at medium concentrations of Cl−, {111}-bound octahedral AgCl crystals will transform into 3D 12-pod AgCl crystals as the concentration of Cl− ions increases. Under the condition of higher concentrations of Cl−, {111}-bound octahedral AgCl crystals will transform into hexapods with mace pods AgCl crystals as the concentration of Cl− ions increases. According to the experimental results, we proposed the growth mechanism of AgCl microcrystals. This work not only provides a new method for the synthesis of AgCl crystals with a tunable shape, but also helps to understand the crystal growth mechanism.

Given the prevalence and severity of indoor HCHO pollution, the efficient elimination of HCHO is of great urgency. Hierarchical Pt/δ-MnO2/Mn3O4 constructed from ultrathin δ-MnO2 nanosheets and octahedron-shaped Mn3O4 nanoparticles was synthesized. About 1.19 mg of HCHO was oxidized over 0.1 g of Pt/δ-MnO2/Mn3O4 (0.5 wt% Pt) within 1 h at room temperature. Pt/δ-MnO2/Mn3O4 (0.1 wt% Pt) exhibited higher activity (0.91 mg) than Pt/commercial-MnO2 (0.5 wt% Pt, 0.87 mg). The enhanced performance of Pt/δ-MnO2/Mn3O4 mainly arose from three factors. Hierarchical texture consisting of ultrathin nanosheets and octahedral nanoparticles endowed the catalysts with high mass transfer efficiency and good Pt-dispersion through providing numerous accessible meso-/macropores and abundant available Pt-deposition sites. Ultrathin δ-MnO2 nanosheets with a high proportion of surface atoms offered a large number of active centres and highly mobile lattice oxygen for HCHO adsorption and oxidation. Active surface oxygen could be generated via a dual-pathway including emergence on the surface of Pt atoms and development through Mn4+/Mn3+ cycles, giving rise to a superb catalytic activity. This work provided a feasible approach for synthesizing low-cost catalysts with excellent performance toward HCHO removal at room temperature.

H2O2-intercalated layered titanate H1.07Ti1.73O4 (H2O2-HTO) exhibits a dramatically enhanced ion-exchange capacity and remarkably improved reaction rate with various divalent cations. The intercalation can increase the negative charge density of the TiO6 octahedral layer and the number of ion-exchangeable H+ by forming a Ti(IV)–O–O–H bond that is the driving force to change the ion exchange performance.

Copper containing materials are widely used in a range of catalytic applications. Here, we report the use of Cu K-edge high resolution XANES to determine the local site symmetry of copper ions during the thermal treatment of a Cu-Cr-Fe oxide catalyst. We exploited the Cu K-edge XANES spectral features, in particular the correlation between area under the pre-edge peak and its position to determine the local environment of Cu2+ ions. The information gained from this investigation rules out the presence of Cu2+ ions in a tetrahedral or square planar geometry, a mixture of these sites, or in a reduced oxidation state. Evidence is presented that the Cu2+ ions in the Cu-Cr-Fe oxide system are present in a distorted octahedral environment.

Cesium lead iodide (CsPbI3) perovskite nanocrystals (NCs) suffer from a known transformation at room temperature from their red-emitting (black) to non-emitting (yellow) phase, induced by the tilting of PbI6 octahedra. While the reported attempts to stabilize CsPbI3 NCs mainly involve Pb2+-site doping as well as compositional and/or NC surface engineering, the black phase stability in relation only to the variation of the reaction temperature of CsPbI3 NCs is surprisingly overlooked. We report a holistic study of the phase stability of CsPbI3 NCs, encompassing dispersions, films, and even devices by tuning the hot-injection temperature between 120-170 °C. Our findings suggest that the transition from the black to the yellow phase occurs after over a month for NCs synthesized at 150 °C (150@NCs). Structural refinement studies attribute the enhanced stability of 150@NCs to their observed lowest octahedral distortion. The 150@NCs also lead to stable unencapsulated solar cells with unchanged performance upon 26 days of shelf storage in dry air. Our study underlines the importance of scrutinizing synthesis parameters for designing stable perovskite NCs towards long-lasting optoelectronic devices. publishedVersion

The exploration of two-leg spin-ladder materials is a great challenge to the chemical community since it is one of the most ideal models for the study of low-dimensional magnetism and high-Tc superconductivity. Herein, we report on a successful synthesis of a new Cu2+-based two-leg ladder compound constructed by CuO4Cl2 octahedra along the [101] direction. The magnetic results exhibit a broad peak at Tmax ∼ 265 K, and suggest that CdCu2(SeO3)2Cl2 has a spin singlet ground state. The fitting of the isolated two-leg spin-ladder model shows J⊥/kB = 429 K and J‖/kB = 21 K, leading to a large spin gap of ∼409 K.

A new beryllium-free zincoborate, BaZn3(BO3)2F2, with a KBBF-type structure has been synthesized for the first time. The electrostatic force of interaction in BaZn3(BO3)2F2 provides better linkage in neighboring [ZnBO3F]∞ single layers. BaZn3(BO3)2F2 is the first case of borates with both [ZnO3F] tetrahedra and [ZnO6] octahedra, enriching the structural chemistry of borate system. All the coplanar [BO3] triangles align in the same direction with a high density, which endows BaZn3(BO3)2F2 with a large birefringence of cal. 0.076 at 1064 nm. This work is of great significance to design beryllium-free borates with a KBBF-type structure.

We report four new A-site vacancy ordered thiocyanate double double perovskites, Image ID:d0sc06619b-t1.gif, A = K+, NH4+, CH3(NH3)+ (MeNH3+) and C(NH2)3+ (Gua+), including the first examples of thiocyanate perovskites containing organic A-site cations. We show, using a combination of X-ray and neutron diffraction, that the structure of these frameworks depends on the A-site cation, and that these frameworks possess complex vacancy-ordering patterns and cooperative octahedral tilts distinctly different from atomic perovskites. Density functional theory calculations uncover the energetic origin of these complex orders and allow us to propose a simple rule to predict favoured A-site cation orderings for a given tilt sequence. We use these insights, in combination with symmetry mode analyses, to show that these complex orders suggest a new route to non-centrosymmetric perovskites, and mean this family of materials could contain excellent candidates for piezo- and ferroelectric applications.

Oxynitride perovskites of the type ABO2N have attracted considerable attention thanks to their potential ferroelectric behavior and tunable bandgap energy, making them ideal candidates for photocatalysis processes. Therefore, in order to shed light on the origin of their ferroelectric response, here we report a complete analysis of the structural and vibrational properties of SrNbO2N and SrTaO2N oxynitrides. By employing first-principles calculations, we analyzed the symmetry in-equivalent structures considering the experimentally reported parent I4/mcm space group (with a phase a0a0c− in Glazer's notation). Based on the I4/mcm reference within the 20-atoms unit-cell, we found and studied the ensemble of structures where different octahedral anionic orderings are allowed by symmetry. Thus, by exploring the vibrational landscape of the cis- and trans-type configuration structures and supported by the ionic eigendisplacements and the Born effective charges, we explained the mechanism responsible for the appearance of stable ferroelectric phases in both anionic orderings. The latter goes from covalent-driven in the trans-type ordering to the geometrically-driven in the cis-type configuration. Finally, we found in both cases that the biaxial xy epitaxial strain considerably enhances such ferroelectric response.

Here, we present a heterometallic coordination polymer that exhibits heterogeneous electrocatalytic activities for both water reduction and water oxidation. Treatment of the PtII2PdII2 tetranuclear complex [Pd2{Pt(NH3)2(D-pen)2}2] ([1]; D-H2pen = D-penicillamine) with CoX2 (X = Cl, Br) provided (PtII2PdII2CoII2)n coordination polymers [Co2(H2O)6(1)]X4 ([2]X4), in which the PtII2PdII2 units of [1] are linked by [Co2(μ-H2O)(H2O)5]4+ moieties in a 3D network structure. [2]X4 showed a colour change from orange to dark green upon dehydration, reflecting the geometrical conversion of the CoII centres in [Co2(μ-H2O)(H2O)5]4+ from an octahedron to a tetrahedron by the removal of aqua ligands. While both [2]Cl4 and [2]Br4 electrochemically catalysed water reduction to H2 in the solid state due to the presence of PdII active centres, water oxidation to O2 was catalysed only by [2]Br4, which is ascribed to the presence of Br− ions that mediate the catalytic reactions that occurred at CoII active centres.

Owing to its novel electronic and magnetic properties, two-dimensional CrI3 has great potential in the application of spintronic devices. However, as an inevitable line defect, the properties of the edges of CrI3 remain elusive. Here, via first-principles calculations with spin-orbit coupling, we investigated the thermodynamic stabilities, electronic and magnetic properties of thirteen CrI3 edges with different structures. We showed that zigzag edges are more stable than armchair edges, and a CrI3 nanoribbon can be either metallic or insulating depending on its chemical growth conditions. The edge stability and associated electronic properties can be understood in terms of the octahedron ligand field and electron counting model. In most cases, both the magnetic moment and Curie temperature can be enhanced by edges, which are in startle contrast to the surfaces of three-dimensional ferromagnetic materials, where a magnetic dead layer is often observed.

A new Ni(II) complex [NiL] (complex 1) of an asymmetrically di-condensed N2O3 donor Schiff base ligand, N-salicylidene-N′-3-methoxysalicylidene-1,3-propanediamine (H2L), has been synthesized and utilized for the synthesis of three heterometallic complexes, [(NiL)2Mn(NCS)2(CH3OH)2]·CH3OH (2) [(NiL)2Mn(N(CN)2)2(CH3OH)2]·CH3OH (3) and [(NiL)2Mn2(N3)2(μ1,1-N3)2(CH3OH)2] (4). Single crystal X-ray diffraction analyses show that complexes 2 and 3 have linear trinuclear structures where two tridentate O3 donor (NiL) units are coordinated to the central octahedral Mn(II) centre, whereas complex 4 has a centrosymmetric tetranuclear structure where two binuclear (NiL)Mn units are linked via two phenoxido and two μ1,1-N3 bridges. Among the heterometallic complexes (2–4), only 4 is active towards the catalytic oxidation of 3,5-di-tert-butylcatechol to the corresponding quinone. The turnover number for the aerobic oxidation of 3,5-DTBC is 935 h−1. ESI-mass spectra have been recorded to scrutinize the mechanistic pathway of this catalytic reaction. Variable temperature magnetic susceptibility measurements suggest that complexes 2–4 are antiferromagnetically coupled with coupling constants (J) of −4.84 and −5.23 cm−1 for complexes 2 and 3, respectively and J1 = −2.20 cm−1, J2 = 1.13 cm−1 and J3 = −1.12 cm−1 for complex 4. DFT calculations have been used to rationalize the magnetic super-exchange in complexes 2–4, by computing the theoretical coupling constants and analyzing the spin density plots.

The dioxomolybdenum(VI) complex MoO2Cl2(dmf)2 reacts with Pb(DOPOQ)2 (DOPO = 2,4,6,8-tetra-tert-butyl-1,9-dioxophenoxazinate) to give MoO2(DOPOQ)2, which has an eight-coordinate structure with normal molybdenum-oxo bond distances and angles but elongated distances to the dioxophenoxazine ligand. The dioxo complex is deoxygenated by phosphines to produce octahedral Mo(DOPOCat)2, in which reduction has taken place at the ancillary ligands. This compound in turn reacts with trimethylamine-N-oxide to regenerate MoO2(DOPOQ)2, allowing a catalytic cycle for phosphine oxidation. This represents an example of four-electron nonclassical oxygen atom transfer in which both the oxidized and reduced forms of the metal complexes can be observed.

This study reports the anomalously stabilized low-temperature triclinic phase (δ-WO3) during high energy ball milling (HEBM) of the monoclinic γ-WO3 phase. The transformation evidenced unit cell contraction with distorted structural parameters resulted in a lower symmetry phase. The phase transformation was understood to be HEBM-induced pressure/compression involved atomic displacement and octahedral tilting-driven polymorphic transition. The major distortion/cooperative octahedral tilting occurred on the (020) plane of γ-WO3 parallel to the b axis. The crystallographic origin of such distortions and unit cell compression mechanisms are explained further. The obtained δ-WO3 phase was stable at room temperature owing to its nanocrystalline structure (11 ± 6 nm) that limits reversible and forward transformations of δ-WO3 → γ-WO3 and γ-WO3 → e-WO3, respectively.

We report the synthesis and structures of three luminescent dysprosium(iii) complexes based on fluorinated alkoxide ligands of formulas [Dy(L1)2(THF)4][BPh4]·0.5THF (1), [Dy(L2)2(THF)5][BPh4]·2.5THF (2) and [Dy(L3)2(THF)5][BPh4]·2THF (3) (L1 = (CF3)3CO-, L2 = C6F5C6F4O-, L3 = C6F5C(CH3)O-). Despite the different dysprosium ion geometries (octahedral vs. distorted pentagonal bipyramidal), these systems exhibit a single-molecule magnet (SMM) behavior, but with distinct relaxation dynamics. Moreover, a typical dysprosium-based luminescence is observed for the three complexes, which make them bifunctional magneto-luminescent SMMs. Remarkably, complex 3 exhibits a high anisotropy barrier of 1469 cm-1 and a blocking temperature of 22 K, making it one of the most performant alkoxide-based SMMs with the highest blocking temperature for a luminescent SMM.

Ba3MoNbO8.5 is an oxide ion conductor with an unconventional hybrid crystal structure that is intermediate between the 9R-perovskite (A3B3O9) and the palmierite (A3B2O8). The crystal structure is highly disordered with vacancies distributed across two cation (M(1) and M(2)) and oxygen sites (O(2) and O(3)), with Mo and Nb in variable coordinate environments. M(1)–O(1)–O(2) and M(2)–O(1) sites are associated with the formation of (Mo,Nb)O6 octahedra, whilst tetrahedral units are composed of M(1)–O(1)–O(3) atoms. Upon increasing the temperature, the structure undergoes a change in occupancy in favour of the O(3) site, which results in a change in metal co-ordination as the tetrahedral to octahedral ratio increases. We demonstrate that the structure can also be tuned using externally applied pressure. Variable pressure studies ≤4.8 GPa indicate that densification of the unit cell induces the reverse effect, as the occupancy of the O(2) site increases and the palmierite contribution is suppressed. Our results strongly suggest that by 5.2 GPa the O(3) position will be completely empty as the 9R unit cell stabilises with a network of octahedral MO6 units. Pressure induces a flattening of M(1)O4 tetrahedra in the palmierite layers, as M(1)O6 octahedra become more regular in geometry. Bond valence site energy calculations show that pressure increases the height of all energy barriers to migration along the three-dimensional diffusion pathways, increasing the energy of the dominant pathway from 0.35 to 0.95 eV. The relaxation energy, E2, disappears above 2.8 GPa, when the average polyhedral distortion (σ(R)) falls below 0.07 A, indicating the existence of a critical minimum. The bulk modulus of Ba3MoNbO8.5 is exceptionally low (50(2) GPa) for a layered oxide material and is closer to that of the halide perovskites. These results demonstrate a high degree of flexibility, in terms of the softness of the lattice and variable metal coordination, emphasising the potential for these materials in multi sensory and thin film applications.

Antimony(III) halide based zero dimensional hybrids have gained attention as broadband emitters. Until now, quadrangular pyramidal SbX5 based and octahedral SbX6 based 0D hybrids have been reported utilizing different organic ligands demonstrating some structural tunability affecting their emissive properties. Utilizing a common organic ligand, here we demonstrate the structural tunability (quadrangular pyramidal, octahedral, or a combination thereof) of the metal halide unit in Sb(III)Cl 0D hybrids with contrasting photo-physical properties (broadband, Stokes shift, strong/weak colored emission). The structure–property–mechanism correlation of the synthesized compounds [1 (C12H52Cl18N8O4Sb3; tris Sb green); 2 (C12H50Cl14N8O3Sb2; tris Sb red); 3 (C24H88Cl25N16O4Sb3; tris Sb yellow)] identifies crucial factors that control their emissive properties. The X-ray analysis reveals the structure (1-octahedral; 2-quadrangular pyramidal; 3-combination thereof) and the order of the extent of structural distortion as 1–3 ≪ 2. The metal halide coordination environment asymmetry and its structure are observed to dictate PL emission energy (1-green; 2-red; 3-yellow) as supported by a qualitative Molecular Orbital scheme. The extent of structural distortion guides the observed Stokes shifts (1–165 nm; 2–290 nm; 3–200 nm; 1–3 < 2). Interestingly, the extent of distortion is found to be well correlated with the observed PLQY (1–45%; 2–6%; 3–43%; 1–3 ≫ 2). This report clearly demonstrates the structural tunability and the effect of the metal halide unit structure/distortion in shaping the emissive properties of 0D organic Sb(III) halide hybrids.

Zr(iv) metal-organic frameworks (MOFs) UiO-68 and PCN-57, containing triphenylene dicarboxylate (TPDC) and tetramethyl-triphenylene dicarboxylate (TTDC) linkers, respectively, were doped with an H-shaped tetracarboxylate linker that contains a [2]rotaxane molecular shuttle. The new MOFs, UWDM-8 and UWDM-9, contain a [2]rotaxane crossbar spanning the tetrahedral cavities of the fcu topology while the octahedral cavities remain empty. 13C solid-state NMR (SSNMR) spectra and solution 1H NMR spectra verified that the [2]rotaxanes were included as designed. Variable-temperature (VT) cross polarization (CP) magic-angle spinning (MAS) 13C SSNMR was used to explore the translational motion of the macrocyclic ring in both MOFs. The SSNMR results clearly show that the structure of the linker (TPDCvs.TTDC) affects the shuttling rate of the macrocyclic ring, although questions remain as to how rotation of the central phenylene unit of the strut might also affect the motion of the macrocycle.

Metal halides have potential applications in many optics-related fields, such as birefringence materials. Here, a pentanary fluoride K3Na(TaF7)(SiF6) has been obtained through a facile hydrothermal route. It crystallizes in the orthorhombic space group Immm, and its zero-dimensional framework features isolated SiF6 octahedra and TaF7 monocapped trigonal prisms, a new type of combination representing a new structure-type. It exhibits two wide optical band gaps of 4.46 eV and 5.67 eV which is consistent with DFT calculation. K3Na(TaF7)(SiF6) exhibits a larger birefringence (0.045 at 253.7 nm) compared with the commercial MgF2 crystal.

A water stable proton-conducting material (NH4)5[Zr3(OH)3F6(PO4)2(HPO4)] (ZrP) was hydrothermally synthesized. The three-dimensional (3D) framework of ZrP is composed of ZrF2O4 octahedra and HxPO4 phosphate units forming 18-ring channels through sharing oxygen atoms. Ammonium cations charge balance the anionic framework. Alternating current (AC) impedance measurements on ZrP powder samples show that at 25–60 °C and 98% relative humidity (RH), the proton conductivity is around 10−2 S cm−1, and the activation energy (Ea) is 0.33 eV.

By employing oxygen-containing ligands with strong coordination ability, a mononuclear six-coordinate DyIII complex [Dy(Ph3PO)3(OPhCl2NO2)3] (1) (Ph3PO = triphenylphosphine oxide, Cl2NO2PhOH = 2,6-dichloro-4-nitrophenol) with an octahedral DyO6 coordination environment has been successfully synthesized. Magnetic measurements reveal that complex 1 exhibits field-induced slow magnetic relaxation with an energy barrier of 21.3 K, which provides a rare case for mononuclear octahedral Ln-based complexes with slow magnetic relaxation behavior.

Ni–Al hydrotalcite-like compounds (Ni–Al HTLCs) containing nitrate anions were synthesized and applied in the acetalization of p-anisaldehyde with ethylene glycol under mild reaction conditions. The Ni–Al HTLCs showed good selectivity for acetalization and achieved almost complete conversion of p-anisaldehyde. The Ni–Al HTLCs as water-tolerant Lewis acids were proved to be an efficient and recyclable catalyst for the acetalization. The oxygen vacancies play an important role in the catalytic activity of Lewis acidic sites on the surface of Ni–Al HTLCs. The NO3− anions coordinate to the matrix Ni2+ cations through oxygen atoms to form [Ni(OH)5NO3] units in the distorted octahedral crystal field, and the most oxygen vacancies in freshly-prepared Ni–Al HTLCs result from the strongly distorted [Ni(OH)5NO3] units. The gradual conversion of distorted [Ni(OH)5NO3] units into regular [Ni(OH)6] units will lead to a loss in catalytic activity of Ni–Al HTLCs.

Surface heterojunction engineering has been demonstrated to be an efficient strategy for the spatial charge separation of photocatalysts. As a consequence, the improved photocatalytic activity is highly determined by the atom arrangement and coordination state of a crystallographic plane. A high-index facet exposed with a high density of low-coordination atoms generally displays better catalytic performance than the low-index one because of its high surface energy. Inspired by the above viewpoints, it is proposed that the construction of a surface heterojunction enclosed by different high-index facets or a mixed form of high-index and low-index facets is a promising avenue to further promote the photocatalytic activity. However, the synthesis of high-index facet based photocatalysts is highly challenging for surface heterojunctions. Herein, we prepare a polyhedral 30-faceted Cu2O microcrystal type-II surface heterojunction co-exposed with 24 high-index {332} facets and 6 low-index {001} facets using a capping agent-assisted liquid-phase reduction method. Compared to the common truncated octahedral (14-facet) Cu2O microcrystal co-exposed with 8 {111} and 6 {001} facets, the 30-faceted Cu2O possesses a highly improved photodegradation activity in the case of normalized specific surface area. Density functional theory (DFT) calculations and in situ photodeposition of metal and metal oxide nanoparticle results indicate that the 30-faceted Cu2O microcrystal is a well-matched {332}–{001} type-II surface heterojunction, which presents a beneficial pathway for efficient charge separation and more high-activity sites for photo-redox reaction than the truncated octahedral surface heterojunction. This work confirms the spatial charge separation and high-index facet dependence in polyhedral Cu2O surface heterojunctions, which provides theoretical guidance for surface heterojunction engineering to enhance photocatalytic activity.

Layered heterometallic phosphates {Mn(H2O)4}2Mn(H2O)2Ru2(PO4)4(H2O)2 (1) with a new topology were constructed from Ru2(PO4)46− and Mn2+ in the presence of anions as assisting reactants whose alkaline strength plays a key role in directing a different number of lattice water-intercalated structures. In the presence of CO32− and SO42− as assisting reactants, the assembling reaction in the aqueous solution at room temperature results in compounds 1·10H2O and 1·4H2O, respectively. Single-crystal X-ray diffraction analysis reveals that compounds 1·10H2O and 1·4H2O crystallize in orthorhombic space group Pbca and monoclinic space group P21/c, respectively. The layered structure of 1 is constructed by alternating Ru2O10 tetragonal dipyramid and MnO6 octahedra bridged by PO4 tetrahedra. The neutral heterometallic phosphate layers of 1 are separated by a different number of interlayer lattice water molecules, and hydrogen bonds are responsible for the neutral inorganic layer connection. Magnetism measurements show that compound 1·10H2O exhibits a soft magnet behaviour ordering below 8.5 K with indirect hydrogen bonding between these ferrimagnetic layers, and a reentrant spin-glass-like transition is observed for compound 1·4H2O, exhibiting two steps transition at 8.0 and 12 K, due to a strong competition between intralayer magnetic coupling and interlayer antiferromagnetic interactions mediated through the direct hydrogen bonding.

De/intercalation of K+ ions results in more severe structural change and volume expansion/shrinkage than that of other monovalent ions such as Li+ and Na+ because of the larger K+-ion size. Thus, it is important to develop novel cathode materials with stable three-dimensional crystal structure and large K+ diffusion pathways to prevent severe structural change during repeated K+ de/intercalation. Here, we introduce K4[Mn2Fe](PO4)2(P2O7) composed of three-dimensionally interconnected [Mn, Fe]O6 octahedra and PO4 tetrahedra as a promising cathode material for K-ion batteries. We demonstrate the outstanding electrochemical properties and reaction mechanism of K4[Mn2Fe](PO4)2(P2O7) in a K-ion battery system through combined studies using various experimental techniques and first-principles calculation. K4[Mn2Fe](PO4)2(P2O7) delivers ∼110 mA h g−1 with a high average operation voltage of 3.5 V (vs. K+/K) at C/20 (1C = 117 mA g−1). Even at 5C, its specific capacity is ∼85 mA h g−1, corresponding to ∼77% of the capacity measured at C/20. In addition, K4[Mn2Fe](PO4)2(P2O7) exhibits an outstanding capacity retention of ∼83% after 300 cycles at C/3 with a high coulombic efficiency of more than 99%. These findings confirm the importance of a stable three-dimensional crystal structure for high-performance K-ion batteries.

[Cu4(LRh)4]8− ([1]8−; LRh = Δ-[Rh(L-cysteinate)3]3−), with an empty tetrahedral {CuI4}4+ core, was converted to [Cu4O(LRh)4]8− ([2]8−), with a mixed-valent {CuI2CuII2O}4+ core, in aqueous NaOH. A solid sample of the latter compound was converted back to [1]8− by heating under vacuum, while treatment of [1]8− with aqueous NaSH caused conversion to [Cu6S(LRh)4]8− ([3]8−), with a stable octahedral {CuI6S}4+ core.

Two new complexes [CoIII2CoII(μ-OL)2(μ-OOCCH3)2(μ-N3)2(N3)2]·Et2O (1·Et2O) and [NiII5(μ-OL)4(μ-OOCCH3)2(OOCCH3)2(μ-N3)2]·CH3CN (2) (HOL = 2-((2-(pyridin-2-yl)ethylamino)methyl)phenol) have been synthesized and characterized by elemental analysis, IR, and UV/Vis spectroscopy. Structural analysis revealed that 1 is a discrete trinuclear and 2 is a discrete pentanuclear coordination complex. In complex 1, terminal metal (CoIII) is in a distorted octahedral MN4O2 environment where coordination is satisfied by two nitrogen atoms and one oxygen atom of the ligand, and an oxygen atom from the acetate group and two nitrogen atoms from azide (one each from the bridging and terminal ones). The central metal (CoII) is also in a distorted octahedral MN2O4 environment where coordination is satisfied by two oxygen atoms from the phenoxo bridge, two oxygen atoms from the acetate bridge and two nitrogen atoms from the azide bridge. In complex 2, each Ni is in a distorted octahedral MN2O4/MN3O3 environment where coordination is satisfied by different donor atoms (amine, pyridine, acetate, phenolate and azide). Direct current (DC) variable-temperature magnetic susceptibility measurements on polycrystalline samples of 1·Et2O and 2 were carried out in the temperature range of 1.8–300 K. The magnetic behaviour of 1·Et2O indicates the presence of magnetic anisotropy of the cobalt(II) ion. The magnetic data of 2 reveal the coexistence of antiferromagnetic and ferromagnetic interactions within the Ni5 unit. Theoretical calculations made from the crystal structures reveal a very good agreement with the experimental findings.

To reduce the polluted areas caused by the migration of radioactive or toxic matter, a clear understanding of soil matrix stability, especially the lattice, is essential under irradiation conditions like those of β-ray irradiation. In reality, the matrix of soil or clay is silicate, with talc being one of the most simple species with a similar structure to that matter, exhibiting “2 : 1” stacking and a complete crystal. Therefore, in this work, it was irradiated by an electron beam in air with dose up to 1000 kGy. Then, variations in lattice and the intrinsic microstructural transformation process, especially in terms of defect formation and transformation, were explored. The main results show that irradiation led to talc lattice plane shrinkage and amorphization. Shrinkage and amorphization levels in the Z-axis were more serious than those in the Y-axis. For a 1000 kGy-irradiated sample, the shrinkage level of the (002) lattice plane was close to 2% near 0.2 A and that of (020) was close to 1.3% near 0.06 A. Variation in the (002) lattice plane was more obvious than that of (020). The main mechanisms involve the cleavage of tetrahedral Si–O and linkage of tetrahedra and octahedra. Tetrahedral Si–O cleavage was visible, leading to serious amorphization. Nevertheless, lattice plane shrinkage, especially in the Z-axis, was mainly caused by linkage cleavage in this direction. In addition to linkage cleavage, dehydroxylation and H2O volatilization occurred, coupled with H2O radiolysis. Nevertheless, those factors are secondary to lattice variation.