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Four new alkali metal aluminum/gallium iodates, namely A2M(IO3)4(H0.5IO3)2 (A = K, Rb and M = Al, Ga), have been successfully synthesized via a hydrothermal reaction and structurally characterized through single-crystal X-ray diffraction analysis. These compounds are isostructural and crystallize in the P1¯ space group (no. 2) with one formula unit in each unit cell. The rare half-protonated H0.5IO3 building units were identified, and their structure feature isolated [M(IO3)4(H0.5IO3)2]2− anions, which are separated by alkali metal cations. The optical diffuse reflectance spectroscopy measurements associated with the Tauc analysis showed direct energy gaps, which are in good agreement with the theoretical calculation prediction. Moreover, this study also indicates that the electronic properties of these compounds are mainly determined by the IO3 and H0.5IO3 anionic units, and the alkali metal cations show a remarkable effect on their energy gap values, whereas the impacts of the group 13 elements aluminum and gallium are insignificant. [ABSTRACT FROM AUTHOR]

Abstract The present work concerns calcium pyroselenites CaSe 2 O 5 with two independent crystal structures, their difference physical properties and phase transformations. α-CaSe 2 O 5 in orthorhombic form shows 2D calcium oxide anionic layers whereas new compound β-CaSe 2 O 5 crystallizes in monoclinic space group C 2 /c. It's a new structure type with 1D calcium oxide thick chains which are further connected by Se 2 O 5 dimers. Rietveld refinement indicates that the weight fraction for α/β-CaSe 2 O 5 mixture phase was found to be 84.5% and 15.5% for α- and β-CaSe 2 O 5 , respectively. Optical diffuse reflectance spectrum coupled with Kubelka–Munk fit gives a result that α-CaSe 2 O 5 adopts direct optical transition model while β-CaSe 2 O 5 is an indirect semiconductor. The experimental result matches well with the prediction of theory calculation. The optical bandgap values were fitted to be 4.74 and 4.12 eV for α- and β-CaSe 2 O 5 , respectively. Thermal analysis coupled with variable temperature powder XRD indicates the phase transformation between these two phases. Graphical abstract β-CaSe 2 O 5 features a new structure which was reported for the first time. Compare with hyper-symmetric of α-CaSe 2 O 5 , structural differences lead into the changes for their physical performances. Optical properties analysis indicates that α-CaSe 2 O 5 is a direct bandgap semiconductor whereas β-CaSe 2 O 5 features an indirect optical transition. Thermal analysis coupled with variable temperature powder XRD indicates the phase transformation of two phases. fx1 Highlights • β-CaSe 2 O 5 was reported for the first time. • Pure α-CaSe 2 O 5 was obtained under a rapid microwave-assist reaction conditions. • α-CaSe 2 O 5 features a direct optical transition model whereas β-CaSe 2 O 5 is an indirect semiconductor. • Thermal analysis coupled with variable temperature powder XRD indicates the phase transformation of two phases. [ABSTRACT FROM AUTHOR]

Two new alkali boroselenites RbSe3B2O9(OH) and CsSe3B2O9(OH) have been synthesized by traditional solid-state reactions. Single-crystal X-ray diffraction study indicated that they are isostructural and adopt a new type of structure, which crystallizes in the noncentrosymmetric space group P212121. Optical diffuse reflectance spectrum studies emphasized that both are indirect optical transitions with values of 3.79 and 4.17 eV for RbSe3B2O9(OH) and CsSe3B2O9(OH), respectively. Optical analysis revealed a broad transparency window in the 0.3–8.5 μm region for both compounds. In addition, RbSe3B2O9(OH) featured a relatively weak second-harmonic-generation response, and for CsSe3B2O9(OH), the response is 0.8-times that of KH2PO4. Theoretical calculations of band structure, density of state, and linear and nonlinear optical properties were also performed to get insight into the relationships between electronic structures and their optical properties. [ABSTRACT FROM AUTHOR]

The Kurtz-Perry powder technique (KPPT) is widely utilized for the rapid characterization of newly grown nonlinear optical (NLO) materials available in pristine powder form. It assesses the effective nonlinear susceptibility of randomly oriented powder in comparison with a reference material. This technique becomes especially versatile when equipped with a broad wavelength range and intensity tunability because it provides key NLO properties of the materials under investigation, such as the frequency dispersion of the NLO susceptibility, phase-matching (PM) range, and laser-induced damage threshold (LIDT) as a guideline. In this study, wavelength-dependent NLO experiments (λ = 1100 – 3700 nm) were conducted on polycrystalline LiInSe 2 , prepared by high-temperature, solid-state synthesis. Our LiInSe 2 was found to be phase-matchable for λ > 2500 nm and the effective NLO susceptibility was estimated as 20.0 ± 1.9 pm/V, assessed at the static limit using commercial-grade single crystals of AgGaS 2 and AgGaSe 2 that were ground to powders. Alternatively, the effective NLO susceptibility was determined to be twice as large, ~40 pm/V, when utilizing a homemade, microcrystalline AgGaSe 2 reference at the static limit. This severe overestimation of the NLO susceptibility that can occur while working with a homemade standard underscores the importance of using a commercial-grade reference with the KPPT. Furthermore, this study also discusses the LIDT of LiInSe 2 based on intensity-dependent SHG at 1064 nm with picosecond pulses, and compares with those of the commercial-grade AgGaS 2 and AgGaSe 2 , determined under identical conditions. As defect levels can cause widely varying apparent color, thus optical bandgap, in LiInSe 2 , this study stresses the importance of using a high-quality standard when exploiting the KPPT for NLO materials characterization. The role of defects is discussed in terms of χ 2 , phase matching onset and LIDT, parameters that predominantly affect the evaluation of new NLO materials. [Display omitted] • A high-quality NLO reference is necessary for the Kurtz-Perry powder technique. • Broadband measurements best characterize the behavior of candidate NLO materials. • The laser-induced damage threshold of LiInSe 2 is 1.0 GW/cm2 (λ = 1064 nm, τ = 30 ps). • LiInSe 2 has a χ(2) value of ~20 pm/V and is phase matchable for λ > 2500 nm. [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]

Correction for ‘Infrared nonlinear optical properties of lithium-containing diamond-like semiconductors Li2ZnGeSe4 and Li2ZnSnSe4’ by Jian-Han Zhang et al., Dalton Trans., 2015, 44, 11212–11222. [ABSTRACT FROM AUTHOR]

Two new lithium-containing diamond-like semiconductors, Li2ZnGeSe4 and Li2ZnSnSe4, have been prepared by high-temperature, solid-state synthesis. Single crystal X-ray diffraction reveals that both compounds adopt the wurtz–kesterite structure type, crystallizing in the noncentrosymmetric space group Pn. X-ray powder diffraction coupled with Rietveld refinement indicates the high degree of phase purity in which the materials are prepared. Both compounds display optical bandgaps around 1.8 eV, wide optical transparency windows from 0.7 to 25 μm and type-I phase matched second harmonic generation starting at 2500 nm and persisting deeper into the infrared. Using the Kurtz powder method, the second-order nonlinear optical coefficient, χ(2), was estimated to be 19 and 23 pm V−1 for Li2ZnGeSe4 and Li2ZnSnSe4, respectively. Using a 1064 nm incident laser beam with a pulse width (τ) of 30 ps both compounds exhibit a laser damage threshold of 0.3 GW cm−2, which is higher than that of the AgGaSe2 reference material measured under identical conditions. Differential thermal analysis shows that the title compounds are stable up to 684 and 736 °C, respectively. These properties collectively demonstrate that Li2ZnGeSe4 and Li2ZnSnSe4 have great potential for applications in tunable laser systems, especially in the infrared and even up to the terahertz regime. Electronic structure calculations using a plane-wave pseudopotential method within density functional theory provide insight regarding the nature of the bandgap and bonding. [ABSTRACT FROM AUTHOR]

Our exploration in vanadate selenites by using boric acid flux method has successfully lead into a new phase, namely, γ-V 2 Se 2 O 9. Single crystal X-ray diffraction indicates its a new structure which crystallizes in monoclinic space group P 2 1 /c with a lattice parameter of a ​= ​7.4857 (12) Å, b ​= ​7.4388 (8) Å, c ​= ​13.042 (2) Å, β ​= ​106.619 (9)°. Its crystal structure features novel 2D electroneutral [V 2 Se 2 O 9 ] layers composed of 1D [V 2 SeO 9 ]4- chains that are further bridged by Se (1)O 3 triangular pyramids. [V 2 SeO 9 ]4- chain consist corner-sharing of VO 6 and tridentate Se (2)O 3. Unlike previously reported α - and β -V 2 Se 2 O 9 with isolated [V 4 O 18 ]16− tetramers, corner-sharing of VO 6 octahedra lead into a 1D [V 2 O 9 ]8- chain in γ-V 2 Se 2 O 9. X-ray powder diffraction and thermal behavior analysis were performed to study its phase purity and thermal stability. Optical diffuse reflectance spectra associated with Tauc's fitting indicates a direct bandgap semiconductor with an energy value of 2.34 ​eV, which consistent with the theoretical prediction. As a compare, the electronic bandgaps of three polymorphs were studied and shows a sequence of α -V 2 Se 2 O 9 < β -V 2 Se 2 O 9 <γ-V 2 Se 2 O 9. Density of states were also calculated to reveal the origin of the bandgaps and bond interactions. [Display omitted] γ-V 2 Se 2 O 9 was obtained by boric acid flux method in vanadate selenite system. Its crystal structure features novel 2D electroneutral [V 2 Se 2 O 9 ] layers composed of 1D [V 2 SeO 9 ]4- chains that are further bridged by Se (1)O 3 triangular pyramids. [V 2 SeO 9 ]4- chain consist corner-sharing of VO 6 and tridentate Se (2)O 3. UV–Vis diffuse reflectance spectroscopy coupled with Tauc's analysis indicates a direct semiconductor with a bandgap value of 2.34 ​eV, and its energy transition type was further supported by first-principles electronic structure calculation. • γ-V 2 Se 2 O 9 was obtained by boric acid flux method for the first time. • Unlike α - and β -V 2 Se 2 O 9 with isolated [V 4 O 18 ]16− tetramers, corner-sharing of VO 6 forms 1D [V 2 O 9 ]8- chains in γ-V 2 Se 2 O 9. • UV–Vis diffuse reflectance spectroscopy coupled with Tauc's fitting indicates γ-V 2 Se 2 O 9 as a direct bandgap of 2.34 ​eV. [ABSTRACT FROM AUTHOR]

A mixed amines thiogermanate (NH 4) 2 [NH 2 (CH 3) 2 2 Ge 2 S 6 was reported. Its structure features isolated [Ge 2 S 6 4− anions which are separated by NH 4 + and [NH 2 (CH 3) 2 +. UV–Vis diffuse reflectance spectroscopy coupled with Tauc's analysis indicates an indirect optical transition semiconductor with an energy gap value of 3.50 eV. Furthermore the energy transition type was supported by first-principles electronic structure calculation. A mixed amines thiogermanate, namely (NH 4) 2 [NH 2 (CH 3) 2 2 Ge 2 S 6 has been successfully synthesized by solvothermal reaction. Single crystal X-ray diffraction indicates the compound crystallizes in monoclinic space group P 2 1 / c with the lattice parameters: a = 6.9647(14) Å, b = 15.719(3) Å, c = 7.2042(14) Å, β = 92.76(3)°. The structure features a zero-dimensional [Ge 2 S 6 4− anions which are separated by NH 4 + and [NH 2 (CH 3) 2 +. Hydrogen bond interactions play a crucial role in its structure formation. X-ray powder diffraction and TG-DSC measurements were performed to study its phase purity and thermal stability. UV–Vis diffuse reflectance spectroscopy coupled with Urbach fitting indicates an indirect optical transition semiconductor with a bandgap value of 3.50 eV. The result of first-principles electronic structure calculation supported the experimental indirect optical transition but the value was under estimated as 3.061 eV. Density of states and population analysis were also calculated to reveal the origin of the bandgap and bond interaction for its structure formation. [ABSTRACT FROM AUTHOR]

A novel lanthanide germanate, namely RbNdGe 2 O 6 , has been successfully synthesized by high-temperature solid-state reaction in open air atmosphere for the first time. Single crystal X-ray diffraction indicates a 3D framework composed of 1D neodymium oxygen chains connected with cyclogermanate Ge 3 O 9 units with Rb+ located in the internal space. X-ray powder diffraction coupled with Rietveld refinement reveals the sample's phase purity we have prepared. Thermal behavior analysis shows RbNdGe 2 O 6 is very stable, it doesn't decomposition until heated up to 998 ​°C. UV–visible absorption and diffuse reflection spectrum feature characteristic absorption bands of f -electron transition and an optical bandgap value of 4.65 ​eV. Magnetic susceptibilities measurement gives significant antiferromagnetic interactions between magnetic centers. The photodegradation experiments were performed to evaluate photocatalytic activities of RbNdGe 2 O 6. By using P25 as a reference, RbNdGe 2 O 6 features to be an effective visible-light-driven catalyst in photodegrading methylene blue. Although the BET value of RbNdGe 2 O 6 is only 3% that of P25, the photocatalytic activity reaches 0.55 times that of P25. Furthermore, the proposed photocatalytic mechanism which dominated by holes was further verified by adding ammonium oxalate as a quencher. New compound RbNdGe 2 O 6 was reported for the first time. Its structure features a 3D framework composed of 1D neodymium oxygen chains connected with cyclogermanate Ge 3 O 9 units with Rb+ located in the internal space. This material features an impressive visible-light-driven photodegradation methylene blue, and the proposed photocatalytic mechanism was also studied. Image 1 [ABSTRACT FROM AUTHOR]

Two novel alkaline-earth zincophosphites, namely CaZn(HPO3)2 and Ba2Zn(HPO3)3, were successfully synthesized under hydrothermal conditions. CaZn(HPO3)2 exhibits a three-dimensional (3D) anionic framework with a 6-connected uni-nodal pcu α-Po primitive cubic topology, constructed by unique Zn2O8 dimers and HPO3 pseudo-tetrahedra, while Ba2Zn(HPO3)3 displays one-dimensional (1D) [Zn(HPO3)3]4− anionic chains. It is worth mentioning that CaZn(HPO3)2 represents the first example of an alkaline-earth zincophosphite compound with a 3D framework structure. Our research also revealed the importance of both alkaline earth cation sizes and Zn/P ratios in anionic open-framework formation. The crystal structures of both compounds were further verified by energy dispersive spectroscopy, IR spectroscopy and Raman spectroscopy. Optical diffuse reflectance spectra, coupled with Tauc's fitting, revealed direct bandgaps with energy values of 4.33 and 4.48 eV for CaZn(HPO3)2 and Ba2Zn(HPO3)3, respectively, which differ from the prediction of theoretical calculations. Density of states calculations were conducted to reveal the origin of the bandgaps and bond interactions. Both compounds exhibited moderate birefringence values. This work may have implications for the design and synthesis of novel metal phosphites with desired properties. [ABSTRACT FROM AUTHOR]

CsV2(H3O)(HPO3)4 (I) and Ba3V2(HPO3)6 (II) are prepared by hydrothermal reaction of aqueous Cs2CO3 or BaCO3, NaVO3, and H3PO3 (autoclave, 210 °C, 4 d, pH 0.5→1; 83 and 85% yield, resp.). [ABSTRACT FROM AUTHOR]

Two new heterometallic uranyl-organic frameworks (UOFs), [Cd(phen)2(H2O)2][(UO2)2(BDC)3]·2H2O (1) and [Ni(phen)3][(UO2)2(BDC)3]·2H2O (2), were obtained under hydrothermal conditions. Both crystal structures were characterized by single-crystal X-ray diffraction analyses and the results indicate that both complexes feature a similar 2D honeycomb framework that is connected by rigid benzenedicarboxylate (BDC) ligands and uranyl units. BDC works as a linker to bridge neighboring UO22+ units, where UO22+ is tris-chelated. Different guest molecules guided the stacking of 2D layers and lead into their 3D supramolecular crystal structures with different space groups. As a result, 1 crystallized in a polar space group Cc, whereas 2 belongs to a chiral space group P6122. Thermogravimetric measurements were performed to study their thermal stability. UV-visible diffuse reflectance spectroscopy measurements indicate an experimental optical bandgap of 3.87 eV and 3.63 eV, respectively, for 1 and 2. Luminescent studies of both samples show strong green light emissions. [ABSTRACT FROM AUTHOR]

In response to the prevalent issue of thiram as a common pesticide residue on the surface of fruits and vegetables, our research team employed an acidic hydrated metal salt low co-fusion solvent to dissolve cellulose lysis slurry. Subsequently, a regenerated cellulose membrane (RCM) was successfully prepared via sol-gel method. Uniformly sized Ag nanoparticles (NPs) were deposited on RCM utilizing the continuous ion layer adsorption and reaction (SILAR) technique. The resulting Ag NPs/RCM flexible surface-enhanced Raman spectroscopy (SERS) substrates exhibited a minimum detection limit of 5 × 10−9 M for Rhodamine 6G (R6G), demonstrating good uniformity (RSD = 4.86 %) and reproducibility (RSD = 3.07 %). Moreover, the substrate displayed a remarkable sensitivity of 10−10 M toward thiram standard solution. Given its inherent flexibility, the substrate proves advantageous for the detection of three-dimensional environments such as fruit and vegetable surfaces, and its practicality has been confirmed in the detection of thiram residue on apples, tomatoes, pears, and other fruits and vegetables. • "Gel-like" RCM provide more efficient adhesion to collect target molecules. • RCM-based substrate materials are safer and more environmentally friendly. • "Gel-like" RCM is more conducive to the formation of high-density SERS "hot spots." • The method based on "wiping" sampling is more convenient. • The minimum detection concentration of thiram can reach 10−10 M. [ABSTRACT FROM AUTHOR]

The new, quaternary diamond-like semiconductor (DLS) Cu4MnGe2S7 was prepared at high-temperature from a stoichiometric reaction of the elements under vacuum. Single crystal X-ray diffraction data were used to solve and refine the structure in the polar space group Cc. Cu4MnGe2S7 features [Ge2S7]6− units and adopts the Cu5Si2S7 structure type that can be considered a derivative of the hexagonal diamond structure. The DLS Cu2MnGeS4 with the wurtz-stannite structure was similarly prepared at a lower temperature. The achievement of relatively phase-pure samples, confirmed by X-ray powder diffraction data, was nontrival as differential thermal analysis shows an incongruent melting behaviour for both compounds at relatively high temperature. The dark red Cu2MnGeS4 and Cu4MnGe2S7 compounds exhibit direct optical bandgaps of 2.21 and 1.98 eV, respectively. The infrared (IR) spectra indicate potentially wide windows of optical transparency up to 25 μm for both materials. Using the Kurtz–Perry powder method, the second-order nonlinear optical susceptibility, χ(2), values for Cu2MnGeS4 and Cu4MnGe2S7 were estimated to be 16.9 ± 2.0 pm V−1 and 2.33 ± 0.86 pm V−1, respectively, by comparing with an optical-quality standard reference material, AgGaSe2 (AGSe). Cu2MnGeS4 was found to be phase matchable at λ = 3100 nm, whereas Cu4MnGe2S7 was determined to be non-phase matchable at λ = 1600 nm. The weak SHG response of Cu4MnGe2S7 precluded phase-matching studies at longer wavelengths. The laser-induced damage threshold (LIDT) for Cu2MnGeS4 was estimated to be ∼0.1 GW cm−2 at λ = 1064 nm (pulse width: τ = 30 ps), while the LIDT for Cu4MnGe2S7 could not be ascertained due to its weak response. The significant variance in NLO properties can be reasoned using the results from electronic structure calculations. [ABSTRACT FROM AUTHOR]

Nano α-glycine crystals, γ-glycine crystals, and amorphous solid dispersion (ASD) of glycine were prepared through solvent-free ball milling of commercial α-glycine. The solid-state polymorph conversion of glycine from α to γ was completely realized by ball milling with 0.2 wt.% NaCl for 1 h or by ball milling with 0.02 wt.% NaCl for 1 h with subsequent storage for one week. The ASD of glycine was prepared by ball milling α-glycine with an equal amount of CaCl 2 for 1 h. We studied the effect of inorganic salt types and their concentrations on the extent of polymorph conversion and amorphization of glycine in our experiments. This solvent-free ball milling method could be used for the synthesis of polymorphs and amorphous phase of drugs and other organic materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • BCM as SERS substrate has little background peak interference. • "Gel-like" BCM is more conducive to the formation of high-density SERS "hot spots." • Flexible SERS substrate based on cellulose membrane has better stability. • SERS sensor based on adapter have high specificity recognition ability. • The minimum detection limit of DTX-1 can reach 9.5 × 10−10 M. Diarrheal shellfish toxins are considered one of the most lethal red tide algae toxins in the worldwide. In this work, we propose an Ag NPs-loaded bacterial cellulose membrane (BCM) surface-enhanced Raman scattering (SERS) sensor based on an aptamer (Apt) for the ultrasensitive detection of dinophysistoxin (DTX-1), a type of diarrheal shellfish toxin. During drying, Ag NPs can be further densified on "gel-like" BCM to form high-density SERS "hot spots". We developed the "Apt-SH@Ag NPs@BCM" SERS sensor and used the competition of DTX-1 and complementary base (Cob) in the process of base complementary pairing to achieve SERS detection of DTX-1, with a minimum detection limit of 9.5 × 10−10 mol/L. Sample assays showed DTX-1 recovery rates ranging from 95.8% and 108.2% and the detection results were comparable to those obtained by LC–MS. Therefore, this work holds great potential for detecting of toxic substances in shellfish products, especially for the oyster (portuguese oyster) and mussel (blue mussel). [ABSTRACT FROM AUTHOR]

Through the incorporation of Cu(II) ions as additional connecting nodes to form heterometallic uranyl-organic frameworks with rigid ligands, we have successfully synthesized three extended complexes with varying dimensions. Notably, complex 1 features a robust 3D cds net structure and demonstrates exceptional thermal stability above 250 °C. [Display omitted] By introducing Cu(II) ions as additional connecting nodes to construct stable heterometallic uranyl-organic frameworks (UOFs) with thiophene-2,5-dicarboxylic acid (H 2 TDC) and N -donor auxiliary ligands, three new uranyl complexes, namely, [Cu(phen)(UO 2)(TDC) 2 ] (1), [Cu(phen-NO 2) 2 (UO 2)(TDC) 2 ]·3H 2 O (2), and [Cu(phen-NH 2)(H 2 O) 2 (UO 2)(TDC) 2 ]·4H 2 O (3) (phen = 1,10-phenanthroline) have been successfully synthesized by hydrothermal reaction. Complex 1 exhibits a rare three-dimensional (3D) network structure of cds topology connected by UO 2 , Cu(phen), and TDC units. Both complexes 2 and 3 feature similar one-dimensional chain structures based on UO 2 , TDC, Cu(Phen-NO 2) 2 and UO 2 , TDC, Cu(phen-NH 2)(H 2 O) 2 respectively. The N -donor auxiliary ligands play a key role in determining their structural dimensionalities and bandgaps formation. Among the three uranyl complexes, phen with a smaller size than its derivatives, phen-NO 2 and phen-NH 2 , was found to be favorable for constructing 3D UOFs. Moreover, complexes with both phen-NO 2 and phen-NH 2 showed varying degrees of redshift on optical spectra. The UV–Visible diffuse-reflectance spectra, analyzed with Tauc's fitting in considering Urbach tailing, revealed an indirect bandgap of 2.94 eV, an indirect bandgap of 2.67 eV, and a direct bandgap of 2.45 eV for 1 , 2 and 3 , respectively. Moreover, thermogravimetric analyses indicate that 3D anhydrous uranyl complex 1 possessed a robust structure and excellent thermal stability above 250 ℃. [ABSTRACT FROM AUTHOR]

• Potassium hydrogen phthalate obtained by hydrolyzing phthalate plasticizer has stronger SERS signal. • The minimum detection limit of potassium hydrogen phthalate can reach 10−9 M. • Hydrolysis greatly reduces the interference of other complex components in oil and fat to the SERS signal of analyte. • The total content of plasticizer in 5 groups of oil samples was successfully detected, and the recovery rate was between 94.5% and 106.0%. As a widely used industrial additive of plastic products, phthalate ester (PAE) plasticizers can easily migrate into food, threatening human health. In this work, we proposed a rapid, precise, and reliable method to detect PAE plasticizers in edible oils by using surface-enhanced Raman spectroscopy (SERS) technology. A two-dimensional (2D) silver plate synergizing with a nanosilver sol was prepared as a substrate for SERS to detect potassium hydrogen phthalate (PHP), a hydrolysate of a PAE plasticizer. Detection conditions, such as pH values, drying times, and hydrolysate interference, were optimized. The working curve was well fitted with a linear parameter R2 of 0.9994, and the minimum detection limit was evaluated as 10−9 mol/L. Furthermore, the detection accuracy was supported by five edible oil samples. Therefore, using SERS technology to detect PHP is expected to provide an avenue for PAE plasticizer detection in oils and fats, and it features promising potential applications in food safety. [ABSTRACT FROM AUTHOR]

Herein, unprecedented NLO-brominated tin hypophosphites, namely [Sn2(H2PO2)3]Br, were discovered via a facile surfactant-induced method, which displayed a moderate powder SHG intensity (3.0 × KDP) in type – I phase matching behavior. This complex has high chemical and thermal stability at room temperature. DFT calculations and SHG coefficient analyses revealed that the alignment of the SHG-active-units SnO3 trigonal pyramids and Br− anions in its structure mainly contribute to the macroscopical SHG behaviors. [ABSTRACT FROM AUTHOR]

High-temperature, solid-state synthesis in the Li 2 MnSnS 4 system led to the discovery of two new polymorphic compounds that were analyzed using single crystal X-ray diffraction. The α-polymorph crystallizes in Pna 2 1 with the lithium cobalt (II) silicate, Li 2 CoSiO 4 , structure type, where Z =4, R 1=0.0349 and wR 2=0.0514 for all data. The β - polymorph possesses the wurtz-kesterite structure type, crystallizing in Pn with Z =2, R 1=0.0423, and wR 2=0.0901 for all data. Rietveld refinement of synchrotron X-ray powder diffraction was utilized to quantify the phase fractions of the polymorphs in the reaction products. The α/β-Li 2 MnSnS 4 mixture exhibits an absorption edge of ∼2.6–3.0 eV, a wide region of optical transparency in the mid- to far-IR, and moderate SHG activity over the fundamental range of 1.1–2.1 μm. Calculations using density functional theory indicate that the ground state energies and electronic structures for α- and β - Li 2 MnSnS 4 , as well as the hypothetical polymorph, γ-Li 2 MnSnS 4 with the wurtz-stannite structure type, are highly similar. [ABSTRACT FROM AUTHOR]

• Cu 4 ZnGe 2 Se 7 is a new diamond-like semiconductor with the Cu 4 NiSi 2 S 7 structure type. • CZGSe and Cu 4 ZnGe 2 Se 7 possess optical bandgaps of 1.38 and 0.91 eV, respectively. • CZGSe and Cu 4 ZnGe 2 Se 7 are air stable and have wide windows of optical transparency. • CZGSe exhibits a strong second harmonic generation response at λ = 2900 nm. • CZGSe is an excellent candidate for low-powered infrared nonlinear optical devices. [Display omitted] In this study, two quaternary diamond-like semiconductors (DLSs) in the Cu-Zn-Ge-Se system, the known Cu 2 ZnGeSe 4 (also referred to as CZGSe) and the new Cu 4 ZnGe 2 Se 7 , are compared in terms of their crystal structures, electronic structures and physicochemical properties. Both compounds were prepared by high-temperature, solid-state synthesis at 800 °C. Single crystal X-ray diffraction was used to determine the structure of Cu 4 ZnGe 2 Se 7. The structures of both Cu 2 ZnGeSe 4 and Cu 4 ZnGe 2 Se 7 can be considered as derivatives of cubic diamond. Cu 4 ZnGe 2 Se 7 , with a reduced symmetry due to the cation ordering pattern, adopts the Cu 4 NiSi 2 S 7 structure type, with space group C 2. The corner-sharing tetrahedra in Cu 4 ZnGe 2 Se 7 are slightly distorted because the charge for some of the S2- anions is not compensated by the first-nearest-neighbor cations. Rietveld refinements using synchrotron X-ray powder diffraction data were used to assess the phase purity of the samples and confirm the bulk structural behavior. Diffuse reflectance UV/Vis/NIR spectroscopy shows that Cu 2 ZnGeSe 4 and Cu 4 ZnGe 2 Se 7 have direct optical bandgaps of 1.38 and 0.91 eV, respectively. Electronic structure calculations implementing density functional theory confirm the direct bandgap for Cu 4 ZnGe 2 Se 7 , with a calculated value of 0.62 eV. Both compounds are air stable, thermally stable up to relatively high temperatures, undergo phase transitions and have wide windows of optical clarity. The Kurtz-Perry powder technique was used to determine the second harmonic generation (SHG) responses using a commercial AgGaSe 2 standard. While Cu 4 ZnGe 2 Se 7 displays a weak SHG response, Cu 2 ZnGeSe 4 exhibits a response that is greater than several benchmark materials, with a large SHG coefficient, χ (2) , of 43 ± 6 pm/V at λ = 2900 nm. [ABSTRACT FROM AUTHOR]