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Metal selenites and tellurites have demonstrated excellent second-harmonic generation (SHG) properties in inorganic solid compounds, such as strong SHG efficiency, a wide transparent range, appropriate birefringence, etc. During the past ten years, important progress has been achieved in this field. The largest SHG efficiency of selenites and tellurites reached 13.5 × KDP (BiFSeO3) and 2 × KTP (CdTeMoO6), respectively. The shortest UV absorption edge of tellurites has been pushed to 205 nm in BaF2TeF2(OH)2 successfully. In terms of the chemical compositions, research studies are no longer concentrated on d0 transition metal compounds only, and the most electronegative fluorine has been used increasingly to widen the optical bandgaps and enrich the structural types of the materials. This paper reviewed the recent developments of selenite and tellurite based SHG materials. Challenges in creating new high powered SHG materials and perspectives for future work are presented. [ABSTRACT FROM AUTHOR]

Systematic explorations of new compounds in the cadmium iodate system by hydrothermal reactions led to two layered iodates, namely, Cd(IO 3 )X (X=Cl, OH). Cd(IO 3 )Cl crystallizes in the orthorhombic space group Cmca (No. 64) whereas Cd(IO 3 )(OH) crystallizes in the orthorhombic space group Pnma (No. 62). Cd(IO 3 )Cl displays a unique double layered structure composed of [ Cd − O 3 Cl ] n ∞ 1 chains. Cadmium octahedrons form a 1D chain along the a -axis through edge sharing, and such chains are further interconnected via IO 3 groups to form a special double layer on (020) plane. Cd(IO 3 )(OH) also exhibits a layered structure that is composed of cadmium cations, IO 3 groups and hydroxyl ions. Within a layer, chains of CdO 6 edge-shared octahedra are observed along the b -axis. And these chains are connected by IO 3 groups into a layer parallel to the bc plane. Spectroscopic characterizations, elemental analysis, and thermogravimetric analysis for the reported two compounds are also presented. [ABSTRACT FROM AUTHOR]

Systematic explorations of new compounds in the La3–V4ﵞiodate system led to three new lanthanum(iii) vanadium iodates, namely, LaVO(IO3)5, LaV2O6(IO3), and LaVO2(IO3)4·H2O. LaVO(IO3)5is isostructural with LaTiO(IO3)5and its structure contains a 0D [VO(IO3)5]3−anionic unit composed of one VO6octahedron linked to five IO3−groups. Such 0D anionic units are separated by La3誉. LaV2O6(IO3) exhibits a unique 3D framework composed of 1D [V2O6]2−ladder like chains and 2D [La(IO3)]2閬麮. LaVO2(IO3)4·H2O is isostructural with LnMoO2(IO3)4(OH) (Ln = La, Nd, Sm, Eu) with a polar space group P21, its structure contains a novel 0D [VO2(IO3)4]3−anionic unit composed of one VO6octahedron linked with four IO3−groups and two terminal O2−anions. Such 0D anionic units are separated by La3誉. The structure of LaVO2(IO3)4·H2O can also be described as the 8-MR channels of the 3D [La(IO3)4]−anion being filled by the VO6octahedra and lattice water molecules. LaVO2(IO3)4·H2O displays a weak SHG response of about 0.2 times that of KDP. Optical, thermal stability and magnetic susceptibility measurements as well as theoretical calculations have also been performed. [ABSTRACT FROM AUTHOR]

Two new examples of mixed metal copper(i) sulfites, namely, Na3Mn2Cu(SO3)4(H2O)5(1) and NaMn4Cu(SO3)5(H2O)3(2), have been synthesized and structurally characterized. The 1D structure of 1is built from a chain of [Mn2Cu(SO3)4]3−bridged by Na+ions whereas the structure of 2features a complicated 3D framework in which Mn8O36octanuclear clusters are bridged by sulfite anions and copper(i) ions into a 3D [CuMn4(SO3)5(H2O)3]2−network. The eight-coordinated sodium(i) ions are located at the cavities of the 3D structure. In both compounds, the oxygen atoms of the sulfite anion are bonded to Mn(ii) ions whereas the sulfur atom is coordinated to the Cu+ion. Magnetic measurements indicate that there exists antiferromagnetic interactions between Mn(ii) centers in both compounds. [ABSTRACT FROM AUTHOR]

Abstract: Two new quaternary strontium selenium(IV) and tellurium(IV) oxychlorides, namely, Sr3(SeO3)(Se2O5)Cl2 and Sr4(Te3O8)Cl4, have been prepared by solid-state reaction. Sr3(SeO3)(Se2O5)Cl2 features a three-dimensional (3D) network structure constructed from strontium(II) interconnected by Cl−, SeO3 2− as well as Se2O5 2− anions. The structure of Sr4(Te3O8)Cl4 features a 3D network in which the strontium tellurium oxide slabs are interconnected by bridging Cl− anions. The diffuse reflectance spectrum measurements and results of the electronic band structure calculations indicate that both compounds are wide band-gap semiconductors. [Copyright &y& Elsevier]

Abstract: The crystal structures and luminescent properties of lanthanide phosphonates are reviewed. The structural elucidation for lanthanide phosphonates is difficult due to its low solubility and poor crystallinity. To overcome these problems, two types of synthetic techniques were applied: attaching various functional groups or introducing a second metal linker. By attaching various types of functional groups to the phosphonate ligand, lanthanide phosphonates with 0D, 1D, 2D and 3D structures have been isolated. Using the acidic metal linker such as oxalate usually leads to compounds with a complicated 3D network structure whereas a basic second metal linker such as phen helps the formation of compounds containing the polynuclear clusters. Phosphonic acids are versatile ligands that can adopt a number of coordination modes depending on the cation size, temperature and the pH value of the reaction media. The luminescence properties of some lanthanide phosphonates are also discussed. [Copyright &y& Elsevier]

Abstract: Two homochiral metal amino-carboxylate–phosphonate hybrids, namely, [Co2Cl(S-HL)(H2O)5]Cl·H2O 1 and Sr2(S-HL)(NO3)2(H2O)·H2O 2 (S-H3L= S-HO2CC4H7NCH2PO3H2) have been synthesized by the reaction of the enantiopure S-H3L ligand with cobalt(II) chloride or strontium nitrate under acidic condition at room temperature. The structure of compound 1 features a novel 3D framework with helical chains and channels. Compound 2 has a layered structure in which the 1D chains of edge-sharing SrO8 and SrO9 polyhedra are interconnected by phosphonate ligands. [Copyright &y& Elsevier]

Abstract: A new Zintl phase, Sr5In2Bi6, has been synthesized by solid-state reactions of the corresponding elements in a stoichiometric ratio in welded niobium tube at 750°C. Its structure was established by single-crystal X-ray diffraction. Sr5In2Bi6 crystallizes in the orthorhombic space group Pbam (No. 55) with cell parameters of a =24.4500(3), b =7.8800(8), c =4.7400(5)Å and V =913.2(2)Å3. It belongs to the Ca5Al2Bi6 structure type and its structure features one-dimensional anionic double chains of [In2Bi6]10− with the Sr2+ ions as spacers. Within the double anionic chain, the In atom is four-bonded by four Bi atoms in a tetrahedral geometry, and these InBi4 tetrahedra are interconnected into a 1D chain via corner-sharing, each pair of such chains are further condensed into a double chain via Bi–Bi bonds. Results of extended Hückel band structure calculations indicate that Sr5In2Bi6 is a semiconductor with a band gap of ∼1.5eV. Sr5In2Bi6 is diamagnetic based on magnetic property measurements. [Copyright &y& Elsevier]

By introduction of oxalate as the second ligand, three novel luminescent lanthanide tetraphosphonates with two types of structures, namely, [La2(ox)2(H6L)]·2H2O (1, H8L = (H2O3PCH2)2NCH2CH2CH2CH2N(CH2PO3H2)2) and Ln2(ox)2(H6L)(H2O)2·4H2O(Ln = Nd, 2; Eu, 3), have been prepared and structurally characterized. The interconnection of La(III) ions in 1 by bridging H6L anions resulted in a 3D network with tunnels running along the a-axis, the oxalate anions are located inside the above tunnels, and each forms two five-membered chelating rings with two La(III) ions. All four phosphonate groups of the H6L anion are bidentate and singly protonated; its two amine groups are also protonated. Compounds 2 and 3 are isostructural, and their structures feature a pillared layered structure. The layer is formed by Ln(III) ions interconnected by oxalate and −NH(CH2PO3H)2 moieties of H6L anions, and the organic groups of the tetraphosphonate ligand act as the pillars. Alternatively, their structures can be described as the lanthanide tetraphosphonate layers being cross-linked by oxalate anions (pillars). The H6L anions in 2 and 3 are hexadentate, and each bridges with six Ln(III) ions; two phosphonate groups are bidentate, and the other two are unidentate. Compounds 1, 2, and 3 exhibit strong emission bands in the blue, red light, and near-IR region, respectively. By introduction of oxalate as the second ligand, three novel luminescent lanthanide tetraphosphonates with two types of structures, namely, [La2(ox)2(H6L)]·2H2O (1, H8L = (H2O3PCH2)2NCH2CH2CH2CH2N(CH2PO3H2)2) and Ln2(ox)2(H6L)(H2O)2·4H2O (Ln = Nd, 2; Eu, 3), have been prepared and structurally characterized. The structures of 1−3 can be viewed as lanthanide-tetraphosphonate-based open frameworks being decorated by the second ligand. Compounds 1, 2, and 3 exhibit strong emission bands in the blue, red light, and near-IR region, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Three new divalent metal(II) aminodiphosphonates with a layered structure have been synthesized by hydrothermal reactions, namely, Zn(H2L1) (1), Cd2(L1) (2) (H4L1=butyl-N(CH2PO3H2)2), and Zn3(HL2)2·1.5H2O (3), (H4L2=cyclo-hexyl-N(CH2PO3H2)2). The 〈100〉 2D zinc(II) phosphonate layer in Zn(H2L1) 1 is built from ZnO4 tetrahedra interconnected by aminodiphosphonate ligands. One phosphonate group of the ligand is tridentate whereas the other one is 1H-protonated and unidentate. The amine group is also protonated. In Cd2(L1) 2, one Cd(II) ion is octahedrally coordinated by one nitrogen atom and five phosphonate oxygen atoms from four L1 anions, whereas the other one is five-coordinated by five phosphonate oxygen atoms in a distorted square pyramidal geometry. The aminodiphosphonate ligand is fully deprotonated, and acts as a undecadentate metal linker. The CdO5N and CdO5 polyhedra are interconnected via edge- and corner-sharing into a 1D chain along b-axis, and such chains are bridged by the diphosphonate ligands into a 〈200〉 metal phosphonate layer. The 〈−101〉 and 〈−202〉 metal phosphonate layers in Zn3(HL2)2·1.5H2O (3) are based on ZnO4 tetrahedra crosslinked by bridging aminodiphosphonate ligands. Both phosphonate groups of the aminodiphosphonate ligand have been deprotonated and are tridentate metal linkers. The amine group remains 1H-protonated. All three compounds exhibit broad emission band in the blue light region. [Copyright &y& Elsevier]

Abstract: Reactions of transition metal(II) salts with three aminophosphonic acids, 1-[(H2O3PCH2)2NCH2CH2−]-piperazine-4-CH2PO3H2 (H6L1), 3-pyridyl-CH2N(CH2PO3H2)2 (H4L2) and 4-pyridyl-CH2N(CH2PO3H2)2 (H4L3) afforded three new metal phosphonates, namely, Cu(H4L1)·2H2O (1), Co(H3L2)2·H2O (2) and [Co(H2L3)(H2O)]·H2O (3). The structure of compound 1 features a 1D chain in which the CuN2O3 and CPO3 polyhedra are interconnected by bridging phosphonate ligands to form 1D chains. Compound 2 has a layered structure. The cobalt(II) ions in the octahedral coordination geometries and {CPO3} tetrahedra are interconnected into an inorganic chain via –N(CH2PO3H)2 moieties, and adjacent chains are further bridged by the coordination pyridyl groups of H3L2 into a 2D layer. The structure of compound 3 features a 2D double layered structure, in which the Co(II) ions are interconnected by bridging phosphonate groups into a 1D chain along b-axis. Neighboring chains are interconnected by coordination pyridyl groups into a double layer perpendicular to the c-axis. [Copyright &y& Elsevier]

Abstract: The new nickel selenite chloride, Ni5(SeO3)4Cl2, was obtained by high-temperature solid state reaction of NiCl2, Ni2O3 and SeO2 in a 1:2:4molar ratio at 700°C in an evacuated quartz tube. Its structure was established by single-crystal X-ray diffraction. Ni5(SeO3)4Cl2 crystallizes in the triclinic system, space group P-1 (No. 2) with cell parameters of a=8.076(2), b=9.288(2), c=9.376(2)Å, α=101.97(3), , and . All nickel(II) ions in Ni5(SeO3)4Cl2 are octahedrally coordinated by selenite oxygens or/and chloride anions (([Ni(1)O5Cl], [Ni(2)O4Cl2], [Ni(3)O5Cl], [Ni(4)O6] and [Ni(5)O4Cl]). The structure of the title compound features a condensed three-dimensional (3D) network built by Ni(II) ions interconnected by SeO3 2− anions as well as Cl− anions. Magnetic property measurements show strong antiferromagnetic interaction between nickel(II) ions. [Copyright &y& Elsevier]

Abstract: Hydrothermal reaction of copper(II) acetate, 2,2′-bipyridine (bipy) and NH4VO3 at 170°C lead to a new layered polyoxovanadate with organically covalent-bonded copper(II) complex, Cu2(bipy)2V6O17 (1). Cu2(bipy)2V6O17 (1) is a new copper(II) vanadium(V) oxide featuring a new layered architecture, in which the V2O7 dimeric units and the cyclic tetranuclear V4O12 cluster units are interconnected via corner sharing into a unique one-dimensional {V6O17}4− anionic chain, such chains are further bridged by {Cu(bipy)}2+ complex cations into a 〈010〉 organic–inorganic hybrid layer. [Copyright &y& Elsevier]

Abstract: The first organically templated vanadium tellurites, [H2en][(VO2)(TeO3)]2·H2O (1, en=ethylenediamine) and [H2pip][(VO2)(TeO3)]2 (2, pip=piperazine) have been synthesized by hydrothermal reactions and structurally characterized. Both compounds feature a [(VO2)(TeO3)]− anionic layer containing V2Te2 four-member rings and V4Te4 eight member rings. The vanadium (V) atom is five coordinated by three tellurite oxygens and two terminal oxygen atoms in a distorted trigonal bipyramidal geometry. The interconnection of the VO5 polyhedra by bridging tellurite groups leads to a 2D corrugated anionic inorganic layer. The doubly protonated template cations and the lattice water molecules in 1 are located at the interlayer space and are involved in hydrogen bonding. The doubly protonated template cation in 2 is not involved in hydrogen bonding with the anionic inorganic layer. [Copyright &y& Elsevier]

Abstract: Hydrothermal reactions of lead(II) carbonate with 1,3,5-benzenetricarboxylic acid (H3BTC) and butylimino-bis(methylenephosphonic acid) (CH3CH2CH2CH2N(CH2PO3H2)2, H4L1) or lead(II) acetate with H3BTC and isobutylimino-bis(methylenephosphonic acid) (Me2CHCH2N(CH2PO3H2)2, H4L2) afforded two novel lead(II) carboxylate phosphonate hybrids, namely, Pb5(HL1)2(L1)·H3BTC 1 and Pb4(BTC)(L2)(CH3CO2)(H2O)2·1.5H2O 2. The structure of compound 1 contains a <002> lead(II) diphosphonate hybrid layer formed by Pb(II) ions interconnected by HL1 and L1 anions. In compound 2, the interconnection of Pb(II) ions through bridging diphosphonate L2 anions lead to the formation of the <200> lead(II) diphosphonate 2D layer. In compound 1, the 1,3,5-benzenetricarboxylic acid acts as an intercalated species whereas in compound 2, the 1,3,5-benzenetricarboxylate anion adopts a hexadentate chelating and bridging coordination mode. [Copyright &y& Elsevier]

Abstract: Reaction of lanthanum(III) chloride and SeO2 under acidic condition lead to a new layered lanthanum(III) diselenite hydrogenselenite, La(Se2O5)(HSeO3)(H2O)·H2O. The title compound crystallizes in the orthorhombic space group Pbca with cell parameters of a =7.329 (1), b =11.013 (2), c =22.802 (3) Å. In the title compound the nine-coordinated lanthanum(III) ions are bridged by Se2O5 2− and HSeO3 − anions to form 2D layers normal to the c-axis. The diselenite anion is hexadentate, forming two types of chelating rings, namely a four-membered Ln–O–Se–O ring and a six-membered La–O–Se–O–Se–O ring, and also bridges with two other La(III) ions. The hydrogenselenite group is bidentate bridging and the protonated oxygen atom remains non-coordinated and is involved in the hydrogen bonding with aqua ligand as well as lattice water molecule. [Copyright &y& Elsevier]

Abstract: Hydrothermal reactions of zinc(II) acetate, 2,2′-bipyridine (bipy), TeO2 and NH4VO3 at 170°C lead to a novel organically covalent-bonded zinc(II) vanadium(V) tellurite, Zn2(bipy)2V4TeO14 (1). The structure of 1 features a new type of layered structure built from 1D double chains of Zn(bipy)V3O9 interconnected by 1D chains of Zn(bipy)VTeO6 via V–O–Te bridges. [Copyright &y& Elsevier]

Abstract: Three new Mn(II) diphosphonates have been synthesized by hydrothermal reactions, namely, Mn(H2L1) (1), Mn(H3L1)2 (2) (H4L1 =C6H5CH2N(CH2PO3H2)2) and Mn2(H2L2)2(H2O) (3), (H4L2 =4-CH3–C6H4CH2N(CH2PO3H2)2). The structure of compound 1 features 〈001〉 and 〈002〉 manganese(II) phosphonate layers, in which the Mn(II) ion is five-coordinated by five oxygens from five diphosphonate ligands in a distorted square pyramidal geometry. The Mn(II) ion in compound 2 is octahedrally coordinated by six phosphonate oxygens from six ligands. Neighboring MnO6 octahedra are interlinked by bridging diphosphonate ligands into a polymeric double chain along the c-axis. Such chains are interlinked by strong hydrogen bonds between non-coordinated phosphonate oxygens into a 2D layer. Compound 3 is composed of 〈001〉 and 〈002〉 manganese(II) phosphonate layers, in which each metal ion is octahedrally coordinated by five phosphonate oxygens from four ligands and an aqua ligand. In all three compounds, the amine group of the ligand is protonated and the phenyl group is orientated toward the interlayer space. [Copyright &y& Elsevier]

Abstract: The title new neodymium(III) selenate-selenite was obtained by hydrothermal reactions of neodymium(III) oxide, H2SeO4 and 1,10-phenanthroline at 140°C. Its structure was established by single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic space group C2/c with cell parameters of a = 12.258(2) Å, b = 7.1024(15) Å, c = 13.391(3) Å, β = 104.250(2)°. The structure of Nd2(SeO4)(SeO3)2(H2O)2 is isomorphous with that of Er2(SeO4)(SeO3)2(H2O)2, which was refined in the monoclinic space group C2 with the disordered selenate group. It features an ordered 3D network with channels along b-axis. The selenate or selenite groups alone can form a 2D layer with the Nd(III) ions. IR spectrum, TGA and luminescent studies have also been performed. [Copyright &y& Elsevier]

The new ternary phase Er2Te4O11 was obtained in high yield from high temperature solid state reaction of Er2O3 and TeO2 in a 1:4 molar ratio at 850 °C in an evacuated quartz tube. Its structure was established by single-crystal X-ray diffraction (XRD). The title compound crystallizes in the monoclinic space group C2/c (No. 15) with cell parameters of a = 12.3563(18), b = 5.0970(1), c = 15.996(2) Å, β = 106.146(6)°, V =967.6(2) Å3 and Z = 4. The crystal structure of Er2Te4O11 is iso-structural with Ln2Te4O11 (Ln = Pr, Nd and Ho). It features a porous 3D network built by linear {Te4O11}6- anions interconnected by Er(III) ions. The lone pair electrons of the Te(IV) ion are orientated towards the cavity of the structure. Near IR luminescent spectrum of Er2Te4O11 shows a strong emission bond at 1530 nm with a luminescent lifetime of 0.275 ms. [Copyright &y& Elsevier]

Abstract: The new hypervalent binary phase EuBi2 was obtained from high temperature solid-state reactions of the pure metal elements in welded Ta tubes under argon atmosphere. Its structure was established by single-crystal X-ray diffraction. The title compound crystallizes in the tetragonal space group I41/amd (No. 141) with cell parameters of , and . The structure of EuBi2 is isotypic with HfGa2 and features 1D Bi- zigzag anionic chains along both - and -axes and 2D Bi- square sheets normal to c-axis. It can be formulated as Eu2+(Bi)chain-(Bi)square-. [Copyright &y& Elsevier]

Three new organically templated or organically bonded zinc selenates, namely, {H2bipy}Zn(SeO4)2(H2O)2 1 (bipy=4,4′-bipyridine), {H2pip}{Zn(SeO4)2(H2O)4}·2H2O 2 (pip=piprazine), and Zn(SeO4)(phen)(H2O)2 3 (phen=1,10-phenanthroline) have been synthesized by hydrothermal reactions. The structure of compound 1 features a 1D chain composed of [Zn(SeO4)2(H2O)2]2- anions. Compound 2 has a 2D layer structure built from {Zn(SeO4)2(H2O)4}2- anions that are cross-linked by doubly protonated piperazine cations via N–H⋯O hydrogen bonds. The structure of compound 3 contains a 1D chain of Zn(SeO4)(phen)(H2O)2, such chains are further interlinked by hydrogen bonds and π⋯π interactions to form a 〈200〉 layer. The different roles the templates played have also been discussed. [Copyright &y& Elsevier]

Two isomeric layered lead(II) carboxylate-phosphonates of N-(phosphonomethyl)-N-methyl glycine ([MeN(CH2CO2H)(CH2PO3H2)]=H3L), namely, monoclinic Pb3L2·H2O 1 and triclinic Pb3L2·H2O 2, have been synthesized and structurally determined. Compound 1 synthesized by hydrothermal reaction at 150°C is monoclinic, space group C2/c with a=19.9872(6), b=11.9333(1) and c=15.8399(4) Å, β=110.432(3)°, V=3540.3(1) Å3, and Z=8. The structure of compound 1 features a 〈400〉 layer in which the lead(II) ions are bridged by both phosphonate and carboxylate groups. The lattice water molecules are located between the layers, forming hydrogen bonds with the non-coordinated carboxylate oxygen atoms. Compound 2 with a same empirical formula as compound 1 was synthesized by hydrothermal reaction at 170°C. It has a different layer structure from that of compound 1 due to the adoption of a different coordination mode for the ligand. It crystallizes in the triclinic system, space group P&1macr; with cell parameters of a=7.1370(6), b=11.522(1), c=11.950(1) Å, α=110.280(2), β=91.625(2), γ=95.614(2)°, V=915.3(1) Å3 and Z=2. The structure of compound 2 features a 〈020〉 metal carboxylate-phosphonate double layer built from 1D lead(II) carboxylate chains interconnected with 1D lead(II) phosphonate double chains. XRD powder patterns of compounds 1 and 2 indicate that each compound exists as a single phase. [Copyright &y& Elsevier]

Reactions of lead(II) acetate with m-aminobenzenesulfonic acid (HL1) and 5-sulfoisophthalic acid (H3L2) afforded two new lead(II) sulfonates, Pb(L1)2 1 and Pb2(L2)(μ3-OH)(H2O) 2. In compound 1, the lead(II) ion is eight-coordinated by two sulfonate groups bidentately, two sulfonate groups unidentately and two amino groups from six ligands. Each L1 ligand is tetradentate and bridges with three Pb(II) ions. The interconnection of the Pb(II) ions via bridging sulfonate ligands resulted in 〈100〉 and 〈200〉 layers. In compound 2, one Pb(II) ion is six-coordinated by a carboxylate group bidentately, by two carboxylate groups unidentately, by a sulfonate oxygen atom and by an OH anion, whereas the other one is six-coordinated by a bidentate chelating carboxylate group, two μ3-OH anions, a sulfonate oxygen atom and an aqua ligand. The interconnection of irregular PbO6 polyhedra via carboxylate–sulfonate ligands resulted in the formation of a pillared layered structure with the 2D layer being formed; the lead(II) ions, hydroxyl groups, carboxylate and sulfonate groups and the benzene ring as the pillar agent. [Copyright &y& Elsevier]

Hydrothermal reactions of N,N-bis(phosphonomethyl)aminoacetic acid (HO2CCH2N(CH2PO3H2)2) with metal(II) salts afforded two new metal carboxylate-phosphonates, namely, Pb2[O2CCH2N(CH2PO3)(CH2PO3H)]·H2O (1) and {NH3CH2CH2NH3}{Ni[O2CCH2N(CH2PO3H)2](H2O)2}2 (2). Among two unique lead(II) ions in the asymmetric unit of complex 1, one is five coordinated by five phosphonate oxygen atoms from 5 ligands, whereas the other one is five-coordinated by a tridentate chelating ligand (1 N and 2 phosphonate O atoms) and two phosphonate oxygen atoms from two other ligands. The carboxylate group of the ligand remains non-coordinated. The bridging of above two types of lead(II) ions through phosphonate groups resulted in a 〈002〉 double layer with the carboxylate group of the ligand as a pendant group. These double layers are further interlinked via hydrogen bonds between the carboxylate groups into a 3D network. The nickel(II) ion in complex 2 is octahedrally coordinated by a tetradentate chelating ligand (two phosphonate oxygen atoms, one nitrogen and one carboxylate oxygen atoms) and two aqua ligands. These {Ni[O2CCH2N(CH2PO3H)2][H2O]2}− anions are further interlinked via hydrogen bonds between non-coordinated phosphonate oxygen atoms to form a 〈800〉 hydrogen bonded 2D layer. The 2H-protonated ethylenediamine cations are intercalated between two layers, forming hydrogen bonds with the non-coordinated carboxylate oxygen atoms. Results of magnetic measurements for complex 2 indicate that there is weak Curie–Weiss behavior with θ=−4.4 K indicating predominant antiferromagnetic interaction between the Ni(II) ions. Indication for magnetic low-dimension magnetism could not be detected. [Copyright &y& Elsevier]

Hydrothermal reactions of N-benzyl-iminobis(methylenephosphonic acid), C6H5CH2N(CH2PO3H2)2 (H4L), with lead(II) carbonate in the presence of butane diacid resulted in a new layered lead(II) amino-bisphosphonate, namely, Pb3L(H2L)·1.5H2O 1. When 1,3,5-benzene-tricarboxylic acid (H3BTC) was used instead of butane diacid, a new layered lead(II) amino-bisphosphonate containing noncoordinated H3BTC molecules, Pb3(HL)2·2(H3BTC)·2H2O 2 was isolated. Compound 1 crystallizes in the monoclinic space group P21/c with cell dimensions of a=17.6776(14) A˚, b=10.0111(8) A˚, c=16.6017(13) A˚, β=104.134(2)° and Z=4. Compound 2 crystallizes in triclinic space group P-1 with cell parameters of a=4.8797(4) A˚, b=9.9736(7) A˚, c=24.3631(17) A˚, α=97.680(2)°, β=95.0000(10)°, γ=102.4340(10)° and Z=1. Both compounds feature a layered structure and have a same metal/ligand ratio of 3:2. Compound 1 contains two types of ligands with different charges, −2 and −4, respectively. The lead(II) ions are bridged by bisphosphonate ligands, resulting in a 〈100〉 layer. In compound 2, the interconnection of the lead(II) ions by bridging phosphonate groups resulted in a 〈001〉 layer, with the neutral H3BTC ligand intercalated between two layers, forming hydrogen bonds with lattice water molecules, noncoordinated phosphonate or carboxylate groups. In both compounds, the phenyl groups of the ligands are orientated toward the interlayer space. TGA and IR spectra for both compounds have been also studied. [Copyright &y& Elsevier]

The new binary phase Sr3In11was obtained from high-temperature reactions of the elements in welded Ta tubes. Its structure was established by single-crystal X-ray diffraction. The title compound crystallizes in the orthorhombic space group Immm (No. 71) with cell parameters of a=4.9328(6), b=11.240(1) and c=16.829 (3) A˚. The crystal structure of Sr3In11, isomorphous with the La3Al11 structure, features two types of tunnels along the a-axis that are formed by indium pentagons and hexagons. Its structural relationships with BaIn4 and SrIn4 phases are examined. Extended-Hu¨ckel band structure calculations indicate that the new metallic binary phase has all bonding states optimized in contrast to the hypoelectronic SrIn4. [Copyright &y& Elsevier]

Three new divalent transitional metal succinates with an additional bipy (bipy=4,4′-bipyridine) ligand have been synthesized by hydrothermal reactions and structurally determined. The structure of [Cu(C4H4O4)(bipy)(H2O)2] · 2H2O (1) features a 3D open framework formed by 1D [Cu(bipy)]2+ chains along the diagonal axis of b and -c that are interconnected by Cu(C4H4O4) helixes along the c-axis. The lattice water molecules are located at the cavities of the framework. In Zn(C4H4O4)(bipy) (2), each zinc cation is octahedrally coordinated by two chelate carboxylate groups from two succinates and 2 N atoms from two bipy molecules, and the ZnO4N2 octahedra are interconnected by bridging succinate ligands into a 1D chain along the 〈0 1 1〉 direction. Such chains are further linked into a 〈0 1 1〉 layer via π–π stacking interaction between the pyridine rings. In [Co(bipy)(H2O)4] (C4H4O4) · 4H2O (3), each pair of octahedral cobalt(II) ions is bridged by a bipy ligand, resulting in a 1D [Co(bipy)(H2O)4]2+ chain, and the succinate ligands and lattice water molecules are sandwiched between two [Co(bipy)(H2O)4]2+ chains to form a 〈0 1 1〉 layer via hydrogen bonding. The layers are further interconnected into a 3D network via hydrogen bonds among carboxylate oxygen atoms, aqua ligands, and lattice water molecules. [Copyright &y& Elsevier]

Hydrothermal reactions of lead(II) salts with N-isobutylimino-bis(methylene-phosphonic acid), C4H9N(CH2PO3H2)2 (H4L), under different conditions lead to two new lead(II) diphosphonates, namely, a layered Pb10L2(HL)4 1, and Pb2L 2 with a microporous network structure. [Copyright &y& Elsevier]

Reactions of syn-2pyridinealdoxime (HL) with divalent metal salts in a mixed ethanol/acetonitrile solution resulted in two new metal complexes with different structures. The structure of the zinc complex, Zn4(L)4Cl2(μ3-OH)2 · 4CH3CN (1) features a 12-metallocrown-4 unit. The syn-2pyridinealdoxime ligand adopts a tridentate chelating and bridging coordination mode. The structure of Mn(HL)(SO4)(H2O) (2) contains a double chain along the b-axis, in which the Mn(II) cations are bridged by μ3-SO42− anions. The syn-2pyridinealdoxime ligand chelates with a Mn(II) ion using its two nitrogen atoms. These double chains are further interconnected into a 2D layer parallel to the ab-plane via hydrogen bonds between aqua ligands and the non-coordinated sulfate oxygen atoms. Results of magnetic measurements of complex 2 indicate that there is weak Curie–Weiss behavior with θ=−10(1) K indicating predominant antiferromagnetic interaction between the Mn(II) ions. Indication for magnetic low-dimensional magnetism could not be detected. [Copyright &y& Elsevier]

Two new quaternary rare-earth chalcogenides, KHo2CuSe4 and KEr2CuSe4, were synthesized from the reactions of elements and binary selenides via a two-step flux technique. Single-crystal X-ray diffraction analyses indicate that both compounds crystallize in the orthorhombic KGd2CuS4 structure type with the space group Cmcm (No. 63) and Z=4. The indexed lattice constants and final R factors are as follows: KEr2CuSe4, a=4.061(1) A˚, b=13.748(4) A˚, c=14.150(3) A˚, V=790.1(3) A˚3, R=0.040, Rw=0.051; KHo2CuSe4, a=4.090(2) A˚, b=13.829(3) A˚, c=14.234(5) A˚, V=805.2(6) A˚3, R=0.046, Rw=0.052. The KLn2CuSe4 structure consists of three different building blocks: KSe6 trigonal prisms, LnSe6 octahedra and CuSe4 tetrahedra. The structure is characterized by edge-shared double octahedral Ln2Se10 units that are condensed into infinite chains along the a axis via trans-edge sharing. These double chains are further linked into a puckered layer in the a–b plane via edge-sharing and another corrugated layer in the a–c plane via corner-sharing with neighboring chains. Consequently, the structure actually forms a three-dimensional framework with additional feature from vertex-sharing CuSe4 tetrahedral chains. The K+ cations, located at the cavities defined by Se atoms, are filled in the channels along the a direction to provide appropriate Coulomb traps. Infrared spectra for both compounds show no absorption peaks between 4000 and 500 cm−1, which suggests an optical transparency in the long-wavelength infrared region. [Copyright &y& Elsevier]

This paper comprehensively reviews 63 selenite compounds with bandgaps above 4.2 eV in four major categories. The focus is on their structures, optical properties, and design strategies, offering valuable insights for the future development of UV selenites. [Display omitted] • This article provides the first comprehensive review of UV selenite materials. • The article emphasizes the classification, structure, optical property, and design strategy of UV selenite. • We have summarized UV selenites' distribution by space group, symmetry, chemical composition, and optical properties. • We have offered guidance for UV selenites development, encompassing synthesis, design strategies, and so on. Nonlinear optical materials and birefringent materials are essential components of modern industrial technology. Selenites, owing to the unique stereochemical activity of the lone pair electrons, have a history spanning several decades as both linear and nonlinear optical materials. Up to now (January 16, 2024), nearly 1100 selenite materials have been discovered, some of which exhibit strong second-harmonic generation effects or large birefringence. With the strategic layout of nations and the rapid advancement of modern industrial technology, the demands on the transparency range of linear and nonlinear optical crystals have become increasingly stringent. Crystals transparent only in the visible spectrum are no longer adequate to meet current requirements. Selenites, which have a long history in the field, seem to have encountered a bottleneck in their recent development, primarily due to an excessive focus on their applications in the visible and near-infrared regions while neglecting their potential uses in the ultraviolet (UV) window. To explore new development directions of selenites, our research group is actively investigating their application as UV optical materials. Through a fluorination control strategy, we successfully synthesized a UV nonlinear optical crystal Y 3 F(SeO 3) 4 and a birefringent crystal CaYF(SeO 3) 2 , thereby developing the application of selenites in the UV region. Additionally, we found that some previously reported selenites with band gaps larger than 4.2 eV have not received sufficient attention from researchers, and their potential application in the UV region have been overlooked. To further promote the research progress of UV selenite materials, this paper comprehensively summarizes the reported selenite materials with bandgaps larger than 4.2 eV, totaling 63 compounds across 6 crystal systems and 19 space groups. We provide a detailed analysis of their structures, optical properties, and design strategies. These materials can be classified into four categories based on different anionic groups: simple selenites, fluoride selenites, selenites with tetrahedral groups, and other selenite compounds. Through a comprehensive review of UV selenites, we have identified ions or groups conducive to expanding the band gaps of selenites, proposed several reliable design methods for UV selenites, and offered useful suggestions for the development of UV selenites. Despite having a long history, selenite systems still hold significant untapped potential for further exploration. We hope this review provides valuable guidance and insights for the future development of inorganic selenites. [ABSTRACT FROM AUTHOR]

Reaction of copper(II) chloride with picolinic acid N-oxide (HL) in acetone/THF mixed solvent afforded a novel layered compound, [Cu(L)Cl(H2O)]2, in which each pair of octahedrally coordinated copper(II) ions are bridged by two N-oxide groups to form a Cu2O2 dimeric unit, and such dimeric units are further interconnected via carboxylate groups to form a layer. [Copyright &y& Elsevier]

Fluorine, as the most electronegative element, can replace the oxygen ligands of functional groups under given conditions. These fluoride groups are more or less different from the pure oxide groups in composition, symmetry, polarizability, transmittancy, etc. The rational use of these differences is expected to improve the probability of noncentrosymmetric structures and the comprehensive performance of second-harmonic-generation (SHG) materials. In this feature article, we introduce the recent developments in fluoride selenite and tellurite SHG materials together with highlighting our contributions, including Se(IV) and Te(IV) compounds with (i) d0 transition metal oxyfluoride octahedron, (ii) IIIA metal oxyfluoride octahedron, (iii) fluoride lone pair cation polyhedron, and (iv) other fluoride polyhedron. The future perspectives of fluoride selenite and tellurite SHG materials are also discussed. [ABSTRACT FROM AUTHOR]

UV nonlinear optical materials require the simultaneous achievement of a large second harmonic generation (SHG) coefficient (≥1 × KH2PO4 (KDP), dij > 0.39 pmV−1), wide bandgap (λ < 300 nm, Eg > 4.2 eV), and moderate birefringence (0.05‐0.10@1064 nm) in a single structure. Therefore, designing UV nonlinear optical materials with excellent comprehensive performance is a challenging task. Herein, four UV transparent selenite materials are successfully obtained, namely, Al2(SeO3)3(H2O)3 (1), Ga2(SeO3)3(H2O)3 (2), NaGa3(HSeO3)6(SeO3)2 (3), and Cd5Ga4(HSeO3)2(SeO3)10 (4), through rational design and screening in the pure selenite system. Al2(SeO3)3(H2O)3 (1) and Ga2(SeO3)3(H2O)3 (2) are UV nonlinear optical materials with balanced properties, exhibiting moderate SHG responses (1.2 and 1.1 × KDP), appropriate birefringence (0.084 and 0.076@1064 nm), and wide bandgaps (5.5 and 5.3 eV). Such bandgaps are the largest in the reported pure selenite nonlinear optical (NLO) materials. This work further demonstrates that pure selenite is a good candidate for UV NLO materials. [ABSTRACT FROM AUTHOR]

It has historically been exceedingly challenging to create physically and chemically stable lanthanide compounds with strong second harmonic generation (SHG) due to their strong preference to central symmetry. In this work, five new non‐centrosymmetric lanthanide selenites, namely, Ln2F2(OH2)(MoO3)2(SeO3)2 (Ln = Sm, Eu, Gd, Tb and Dy), are achieved by partial fluorination of the lanthanide oxygen polyhedron. An HF corrosion resistant supercritical hydrothermal method is developed, which is a facile and universal method for HF corrosion and high‐temperature high‐pressure environment. The title compounds displayed a novel 3D framework composed of 1D molybdenum selenite chains bridged by Ln2F2O12(OH2) dimers. Their powder SHG responses showed a large difference, ranging from 1.0 to 9.0 × KH2PO4 (KDP) at 1064 nm. The half‐filled Gd compound exhibited very strong SHG efficiency of up to 1.2 × KTP (KTiOPO4) at 2050 nm. Compounds Tb and Gd are the first lanthanide selenites with SHG intensity reaching KTP level, which is very rare in this system. Furthermore, these compounds can also possess excellent physicochemical stability and strong luminescence emission, indicating that they are promising multifunctional nonlinear optical materials. This work offered an effective way for design and synthesis of multifunctional and high‐performant nonlinear optical materials. [ABSTRACT FROM AUTHOR]

It is a great challenge to develop UV nonlinear optical (NLO) material due to the demanding conditions of strong second harmonic generation (SHG) intensity and wide band gap. The first ultraviolet NLO selenite material, Y3F(SeO3)4, has been obtained by control of the fluorine content in a centrosymmetric CaYF(SeO3)2. The two new compounds represent similar 3D structures composed of 3D yttrium open frameworks strengthened by selenite groups. CaYF(SeO3)2 has a large birefringence (0.138@532 nm and 0.127@1064 nm) and a wide optical band gap (5.06 eV). The non‐centrosymmetric Y3F(SeO3)4 can exhibit strong SHG intensity (5.5×KDP@1064 nm), wide band gap (5.03 eV), short UV cut‐off edge (204 nm) and high thermal stability (690 °C). So, Y3F(SeO3)4 is a new UV NLO material with excellent comprehensive properties. Our work shows that it is an effective method to develop new UV NLO selenite material by fluorination control of the centrosymmetric compounds. [ABSTRACT FROM AUTHOR]

It is a great challenge to develop UV nonlinear optical (NLO) material due to the demanding conditions of strong second harmonic generation (SHG) intensity and wide band gap. The first ultraviolet NLO selenite material, Y3F(SeO3)4, has been obtained by control of the fluorine content in a centrosymmetric CaYF(SeO3)2. The two new compounds represent similar 3D structures composed of 3D yttrium open frameworks strengthened by selenite groups. CaYF(SeO3)2 has a large birefringence (0.138@532 nm and 0.127@1064 nm) and a wide optical band gap (5.06 eV). The non‐centrosymmetric Y3F(SeO3)4 can exhibit strong SHG intensity (5.5×KDP@1064 nm), wide band gap (5.03 eV), short UV cut‐off edge (204 nm) and high thermal stability (690 °C). So, Y3F(SeO3)4 is a new UV NLO material with excellent comprehensive properties. Our work shows that it is an effective method to develop new UV NLO selenite material by fluorination control of the centrosymmetric compounds. [ABSTRACT FROM AUTHOR]

A new alkaline earth–rare earth iodate, Ba2Ce(IO3)8(H2O), has been synthesised by a hydrothermal method and its structure has been determined by single-crystal X-ray diffraction. Ba2Ce(IO3)8(H2O) crystallises in the polar space group Pna21 (No. 33) with unit cell parameters of a = 15.5042(5) Å, b = 7.8841(3) Å, c = 19.5359(8) Å, V = 2388.00(15) Å3, and Z = 4. The structure of Ba2Ce(IO3)8(H2O) is characterised by zero-dimensional (0D) [Ce(IO3)8(H2O)]4− units separated by Ba2+ cations. Large crystals of Ba2Ce(IO3)8(H2O) with dimensions of a few millimetres have been grown. The UV-vis-NIR transmission spectroscopy measurements of the compound showed that it has a short wavelength absorption edge at 381 nm. Ba2Ce(IO3)8(H2O) exhibits a relatively weak second-harmonic-generation (SHG) response, about 0.2 times that of KDP, which is mainly due to the fact that the polarisation effects of the IO3 groups in the structure largely cancel each other out. The relationships between the structure and the physical properties of Ba2Ce(IO3)8(H2O) have also been calculated theoretically. Ba2Ce(IO3)8(H2O) has a band gap of 2.44 eV, which is determined by the Ce–O and I–O interactions and is larger than those of many simple metal iodates. The introduction of alkaline earth metals favours an increase in band gap. Our work shows that the SHG and birefringence properties are closely related to the arrangement of the functional groups in the compounds. [ABSTRACT FROM AUTHOR]

Trigonal planar units with large polarizability anisotropy and high physicochemical stability are ideal structural units for exploring nonlinear optical (NLO) materials. Integrating the merits of two types of triangular‐like moieties, a family of second‐order NLO‐active hybrid halides, MATX (X = Cl (1), Br (2), and I (3)), are achieved. MATX crystallizes in a nonpolar space group of P6¯$P\overline 6 $2c but exhibits the optimal spatial arrangement and superior NLO performance. The low coordination planar trigonal AgX3 units enable segregation in layers of the three‐winged propeller‐like Me3TPA units. All of the layers are packed in a perfect parallel fashion, making the functional materials exhibit superior NLO performances, including the phase matchable behavior with strong SHG responses (6.2/1, 6.5/2, and 7.6/3 times that of potassium dihydrogen phosphate), large birefringence (0.232/1, 0.252/2 and 0.260/3 at 1064 nm), high laser damage threshold, wide transparent window, and easiness of crystal growth. The first‐principles calculations reveal that the coexistence of strong linear and nonlinear optical properties are ascribed to the synergistic effect of the trigonal moieties. This study points out a useful path for the rational design of excellent NLO materials. [ABSTRACT FROM AUTHOR]

Trigonal planar units with large polarizability anisotropy and high physicochemical stability are ideal structural units for exploring nonlinear optical (NLO) materials. Integrating the merits of two types of triangular‐like moieties, a family of second‐order NLO‐active hybrid halides, MATX (X = Cl (1), Br (2), and I (3)), are achieved. MATX crystallizes in a nonpolar space group of P6¯$P\overline 6 $2c but exhibits the optimal spatial arrangement and superior NLO performance. The low coordination planar trigonal AgX3 units enable segregation in layers of the three‐winged propeller‐like Me3TPA units. All of the layers are packed in a perfect parallel fashion, making the functional materials exhibit superior NLO performances, including the phase matchable behavior with strong SHG responses (6.2/1, 6.5/2, and 7.6/3 times that of potassium dihydrogen phosphate), large birefringence (0.232/1, 0.252/2 and 0.260/3 at 1064 nm), high laser damage threshold, wide transparent window, and easiness of crystal growth. The first‐principles calculations reveal that the coexistence of strong linear and nonlinear optical properties are ascribed to the synergistic effect of the trigonal moieties. This study points out a useful path for the rational design of excellent NLO materials. [ABSTRACT FROM AUTHOR]

A series of vanadium selenites covalently bonded with metal-organic complex, namely, Ni(2,2-bipy) 2 V 2 O 4 (SeO 3 ) 2 ( 1 ), Cu(2,2-bipy)V 2 O 4 (SeO 3 ) 2 ·0.5H 2 O ( 2 ) and Cu 2 (2,2-bipy) 2 V 5 O 12 (SeO 3 ) 2 ( 3 ) (2,2-bipy=2,2-bipyridine) have been hydrothermally synthesized and structurally characterized. They exhibit three different structural dimensions, from 0D cluster, 1D chain to 2D layer. Compound 1 features a 0D {Ni(2,2-bipy) 2 V 2 O 4 (SeO 3 ) 2 } 2 dimeric cluster composed of two {Ni(2,2-bipy) 2 } 2+ moieties connected by the {V 4 O 8 (SeO 3 ) 4 } 4- cluster. Compound 2 shows a 1D {Cu(2,2-bipy)V 2 O 4 (SeO 3 ) 2 } n chain in which the {Cu 2 (2,2-bipy) 2 } 4+ moieties are bridged by the {V 4 O 8 (SeO 3 ) 4 } 4− clusters. Compound 3 displays a 2D structure consisted of mixed valence vanadium selenites layers {V IV V V 4 Se IV 2 O 18 } n 4− and {Cu(2,2-bipy)} 2+ complex moieties. The adjacent layers are further interconnected via π-π interactions between the 2,2-bipy ligands exhibiting an interesting 3D supramolecular architecture. Both compound 1 and 2 contain a new {V 4 O 8 (SeO 3 ) 4 } 4− cluster and compound 3 exhibits the first 2D vanadate polyhedral layer in vanadium selenites/tellurites with organic moieties. [ABSTRACT FROM AUTHOR]

We reported the synthesis and crystal structures of alkali metal and alkali-earth metal phosphite, namely, CsV 2 (H 3 O)(HPO 3 ) 4 ( 1 ), and Ba 3 V 2 (HPO 3 ) 6 ( 2 ). Both compounds were prepared by hydrothermal reactions and feature unique new structures. They both exhibit 3D complicated frameworks based on VO 6 octahedra which are connected by HPO 3 tetrahedra via corner-sharing. Alkali or alkali earth metal cations are filled in the different channels of the frameworks. Topological analysis shows that the framework of CsV 2 (H 3 O) (HPO 3 ) 4 ( 1 ) is a new 3,3,3,4,5-connected network with the Schläfli symbol of {4.6 2 } 2 {4 2 .6 6 .8 2 }{6 3 }{6 5 .8}. The investigations of X-ray photoelectron spectroscopy (XPS) and magnetic measurement on CsV 2 (H 3 O)(HPO 3 ) 4 suggest a +3 oxidation state of the vanadium ions in compound 1 . Photocatalytic performance was evaluated by photocatalytic H 2 evolution and degradation of methylene blue, which shows that both compounds exhibit activity under visible-light irradiation. IR spectrum, UV–vis-NIR spectrum and thermogravimetric analysis (TGA) of compounds were also investigated. [ABSTRACT FROM AUTHOR]

Four new alkali metal boroantimonates, namely, A2SbB3O8 (A = Na, K, Rb) and β-RbSbB2O6, have been synthesized by high-temperature solid-state reactions. Isostructural A2SbB3O8 (A = Na, K, Rb) crystallizes in the monoclinic space group P21/c, with structures featuring a novel 3D anionic framework composed of SbO6 octahedra and linear B3O8 groups with 1D tunnels of Sb4B4 8-membered-rings (MRs) along the a-axis, which are filled by alkali metal ions. β-RbSbB2O6 crystallizes in the polar space group Cc, revealing novel 3D anionic networks composed of SbO6 octahedra chains and B2O5 groups with 1D tunnels of Sb4B2 6-MRs along the b-axis and 1D tunnels of Sb3B4 7-MRs along the c-axis. Studies on their optical properties and thermal stability, band structure calculations based on DFT methods and linear optical calculations have also been performed. [ABSTRACT FROM AUTHOR]

Large crystal of the nonlinear optical and polar oxide Cs 2 TeW 3 O 12 with a size of 20×15×4 mm 3 has been grown by the top-seeded solution growth (TSSG) method. This crystal can be thermally stable up to 808 °C and melts incongruently. It possesses a large transparent range of 0.415–5.250 μm. Thermal properties, including thermal expansion, specific heat, thermal diffusivity and thermal conductivity were investigated. The average linear thermal expansion coefficients were calculated based on the measurement in the temperature range of 30–390 °C. It exhibits strong anisotropic thermal expansion which was discussed according to the relationships between the structure and thermal properties. Furthermore, laser-induced damage threshold has been estimated to be 591.28 MW/cm 2 with a laser wavelength of 1064 nm and pulse duration of 8 ns. [ABSTRACT FROM AUTHOR]

Three new octanuclear Th(iv) arsonates, namely [Th8(O)(L)6(HL)6(H2O)12]·19.5H2O (1) (H3L = o-HO3S–C6H4–AsO3H2), [Th8(O)(L)6(HL)6(H2O)10]·17H2O (2) and [Th8(O)(L)6(HL)6(H2O)5]·0.5H2O (3), with o-sulfophenylarsonic acid as the bridging ligand, have been prepared under hydrothermal conditions. Each complex contains [Th8O13]6+ octanuclear cluster cores composed of two [Th4O6]4+ units bridged by a μ2-oxo anion. The structure of compound 1 features a 0D highly symmetric polynuclear cluster encapsulating the octanuclear core of [Th8O13]6+ which is further decorated by six L3− and six HL2− ligands. Compound 2 features one-dimensional chains along the b-axis in which the neighboring clusters similar to 1 are bridged by a pair of sulfophenylarsonate ligands via M–O–S–O–M bridges. Compound 3 with chiral P212121 features two-dimensional cluster layers, in which each cluster connects with four neighbors via four M–O–S–O–M linkages. Compounds 2 and 3 display unusual broad green light emission bands at 523 nm (λex = 320 nm) and 517 nm (λex = 312 nm), respectively, which originate from the ligand-to-metal charge transfer (LMCT) transition. [ABSTRACT FROM AUTHOR]

The first NLO-active metal iodate-phosphates, namely, Cd2(IO3)(PO4) and Cd1.62Mg0.38(IO3)(PO4) (1 and 2), with three types of NLO groups, have been reported. 1 and 2 are isostructural and the structure of 1 features a 3D network formed by the Cd4(IO3)8/4(PO4)6/3 groups. 1 and 2 with strong SHG signals of 4 × and 3.5 × KH2PO4 are promising SHG materials in the visible region. [ABSTRACT FROM AUTHOR]

Three nonlinear optical materials Cd4REO(BO3)3 (RE = Sm, Eu, Tb) have been synthesized through high-temperature solid-state reactions. In their crystal structures, Cd(1)O8 and Cd(2)O6 polyhedra are interconnected via sharing edges and corners into a 3D anion framework with two types of tunnels based on 4- and 7-membered rings; the BO3 groups are grafted into the above-mentioned types, creating new tunnels based on Cd4B3 seven-membered rings, which are filled by RE3+ cations. Powder SHG measurements revealed that the Cd4REO(BO3)3 (RE = Sm, Eu, Tb) samples display SHG signals that are approximately 1.2, 5.6 and 1.5 times that of the KDP sample. In addition, Cd4EuO(BO3)3 and Cd4TbO(BO3)3 emit red and green light, respectively. The lifetime of the Eu(5D0) state for λex,em = 464, 610 nm in Cd4EuO(BO3)3 is measured to be about 1.43 ms whereas the lifetime of the Tb(5D4) state for λex,em = 376, 543 nm in Cd4TbO(BO3)3 is measured to be about 1.01 ms. [ABSTRACT FROM AUTHOR]

Through systematic experiments, two novel mercury iodate sulfates, namely, Hg2(IO3)2(SO4)(H2O) and Hg2(IO3)2(SO4) were obtained. They crystallize in monoclinic space group C2 and C2/c, respectively. Hg2(IO3)2(SO4)(H2O) exhibits the [Hg(IO3)]+ polar cationic layer inherited from Hg(IO3)2 and the three‐dimensional (3D) framework inherited from HgSO4. This enables Hg2(IO3)2(SO4)(H2O) to generate a strong second harmonic generation (SHG) response of 6 times that of KH2PO4 (KDP). The structure of Hg2(IO3)2(SO4) is very similar to that of Hg2(IO3)2(SO4)(H2O), and they can be transformed into each other. Hg2(IO3)2(SO4)(H2O) shows a large optical band gap of 3.98 eV and a high dehydration temperature of 250 °C. This study indicates that by reasonable design, the introduction of multiple functional groups into a compound may combine their advantages to achieve good overall optical performance. [ABSTRACT FROM AUTHOR]