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Inorganic metal chalcohalides, as significant semiconductor materials, have emerged as promising candidates for photoelectric applications. Herein, a new type of quaternary chalcohalide, [Ba4X][In19S32] (X = Cl, Br), has been discovered using the high-temperature halide salt flux method. Single-crystal X-ray diffraction analysis reveals that they are isostructural and crystallize in the tetragonal space group I41/amd (no. 141) featuring the octahedral hole formed by six [InS4]5− tetrahedra filled with a [ClBa4]7+ polycation, surrounded by a three-dimensional covalent framework formed by interconnecting [InS6]9− octahedra through corner-sharing and edge-sharing. Moreover, [Ba4Cl][In19S32] and [Ba4Br][In19S32] exhibit wide optical bandgaps of 2.70 eV and 2.46 eV, respectively, and moderate birefringences (0.044 @ 2100 nm and 0.042 @ 2100 nm, respectively). Specifically, [Ba4X][In19S32] (X = Cl, Br) display remarkable photocurrent responses under simulated solar-light illumination, implying their potential for photocatalytic applications. Theoretical calculations were employed to understand the interrelationship between the optical properties and electronic structure. The study on the synthesis and structure–property relationship analysis of inorganic metal chalcohalides provides new insight into the exploration of promising photoelectric materials. [ABSTRACT FROM AUTHOR]

Stability is a key factor that restricts the practical applications of metal–organic framework (MOF) materials. In this work, we report an ultrastable three-dimensional cage-like MOF, SrCu(HC3N3O3)2, constructed by a polydentate cyanurate ligand and two kinds of different metal nodes. A high ratio of coordination sites in organic ligands, specific coordination of strong acid with a strong base and weak acid with a weak base and double independent completed coordination networks endow SrCu(HC3N3O3)2 with outstanding thermal stability (up to 300 °C) and acid/alkali resistance (pH = 2–14). Moreover, SrCu(HC3N3O3)2 possesses the highest porosity up to 36.7% among cyanuric acid-based MOF materials and exhibits differentiated adsorption of C3H4 (63 cm3 g−1) and C3H6 (51 cm3 g−1). The breakthrough experiment further verified that efficient C3H4/C3H6 separation can be achieved under dynamic conditions by SrCu(HC3N3O3)2. [ABSTRACT FROM AUTHOR]

Metal thiophosphates have outstanding properties for the generation of mid-infrared coherent light and are an emerging nonlinear optical material system. In this study, a new non-centrosymmetric (NCS) quaternary alkaline-earth metal thiophosphate, SrAgPS4, was obtained via a high-temperature solid-state method. The new compound crystallizes in the NCS Ama2 (No. 40) space group and features two-dimensional [AgPS4]2− layers consisting of alternately connected [PS4] and [AgS4] tetrahedra. SrAgPS4 exhibits a strong phase-matched second harmonic generation response (1.10 × AgGaS2 at 2100 nm) and a large band gap (2.97 eV). In addition, theoretical calculations reveal the intrinsic relationship between the electronic structure and optical properties. This work enriches and greatly promotes the research on infrared nonlinear optical materials based on thiophosphates. [ABSTRACT FROM AUTHOR]

Inorganic metal chalcohalides are significant semiconductive materials for photovoltaics, photodetetion and infrared optics. Thus it is considerably rewarding to develop a new synthetic strategy to provide more degrees of freedom for atomic coordination to tune the optical and electronic properties of metal chalcohalides. In this work, the mixed-anion strategy is performed to synthesize two new metal chalcohalides Cs2InPS4X2 (X = Cl, Br) with mixed-anion structure by the reaction of InPS4 and CsX. Single-crystal X-ray diffraction analysis shows that they are isostructural and crystallize in the centrosymmetric space group P21/n, consisting of zero-dimensional structure [In2P2S8X4]4− (X = Cl, Br) built from tetrahedral [PS4]3− and octahedral [InS4X2]7− (X = Cl, Br) through edge-sharing, with Cs cations filling in intervening voids. The UV-vis-NIR diffuse reflectance spectroscopy measurement reveals that Cs2InPS4Cl2 and Cs2InPS4Br2 exhibit large optical bandgaps of 3.21 eV and 3.12 eV, respectively. The electronic structure calculations show that the bandgap mainly originates from the [InS4X2]7− (X = Cl, Br) mixed-anion groups. First-principles calculations indicate that the birefringence of Cs2InPS4Cl2 and Cs2InPS4Br2 is ∼0.08 and ∼0.05 at 2090 nm, respectively. Furthermore, thermal analysis reveals that the Cs2InPS4X2 (X = Cl, Br) are thermostable up to 400 °C. This discovery enriches the structural diversity of inorganic chalcohalides and provides an insight for the exploration of new semiconductive materials. [ABSTRACT FROM AUTHOR]

Noncentrosymmetric (NCS) structure is the precondition for second-order nonlinear optical (NLO) materials. In this work, we present a new strategy for constructing NCS structures, whereby mixed alkali metals make a new NCS chalcogenide, (Na3Rb)Hg2Ge2S8, based on the centrosymmetric (CS) Rb4Hg2Ge2S8. (Na3Rb)Hg2Ge2S8 crystallizes in the polar space group of Pca21, and adopts a filled cristobalite-type structure with a {[HgGeS4]2−}∞ framework formed by the alternating connection of [HgS4] and [GeS4] tetrahedra via corner-sharing and with the mixed alkali metal cations in the cavities of the framework. Structural analysis and theoretical calculations suggest that the ordered and alternating arrangement of NLO-active chromophores, [HgS4] and [GeS4] tetrahedra, induced by partial substitution of alkali metals plays an important role in the enhanced second harmonic generation activity. As such, (Na3Rb)Hg2Ge2S8 exhibits strong second harmonic generation response of 1.4 × AgGaS2 at 2090 nm, wide band gap of 2.76 eV and low melting point of 444 °C. Therefore, this strategy of mixed alkali metals may shed light on structural modification from CS to NCS for new NLO materials. [ABSTRACT FROM AUTHOR]

Metal chalcogenides perform well as mid-infrared nonlinear optical (NLO) materials, especially those with diamond-like (DL) structural features. Starting from the classical AgGaS2 (AGS), we propose a design strategy to enhance the second-harmonic generation (SHG) response by introducing vacancy defects and highly distorted NLO-active units. Hence, a new quaternary chalcogenide AgHgPS4 with a defect DL structure, crystallizing in the non-centrosymmetric monoclinic space group Pn, is successfully synthesized by the substitution of GaS4 units with HgS4 and PS4 units. Detailed experimental results verify that AgHgPS4 exhibits a much stronger SHG response (5.09 × AGS, 2.63 eV) without sacrificing the optical band gap compared with AGS. Moreover, the cation vacancy defects and highly distorted HgS4 units are identified as the crucial driving forces of the large NLO response by partial charge density distributions and dipole moment calculations. [ABSTRACT FROM AUTHOR]

Inorganic metal chalcohalides, as significant semiconductor materials, have emerged as promising candidates for photoelectric applications. Herein, a new type of quaternary chalcohalide, [Ba 4 X][In 19 S 32 ] (X = Cl, Br), has been discovered using the high-temperature halide salt flux method. Single-crystal X-ray diffraction analysis reveals that they are isostructural and crystallize in the tetragonal space group I 4 1 / amd (no. 141) featuring the octahedral hole formed by six [InS 4 ] 5- tetrahedra filled with a [ClBa 4 ] 7+ polycation, surrounded by a three-dimensional covalent framework formed by interconnecting [InS 6 ] 9- octahedra through corner-sharing and edge-sharing. Moreover, [Ba 4 Cl][In 19 S 32 ] and [Ba 4 Br][In 19 S 32 ] exhibit wide optical bandgaps of 2.70 eV and 2.46 eV, respectively, and moderate birefringences (0.044 @ 2100 nm and 0.042 @ 2100 nm, respectively). Specifically, [Ba 4 X][In 19 S 32 ] (X = Cl, Br) display remarkable photocurrent responses under simulated solar-light illumination, implying their potential for photocatalytic applications. Theoretical calculations were employed to understand the interrelationship between the optical properties and electronic structure. The study on the synthesis and structure-property relationship analysis of inorganic metal chalcohalides provides new insight into the exploration of promising photoelectric materials.

Stability is a key factor that restricts the practical applications of metal-organic framework (MOF) materials. In this work, we report an ultrastable three-dimensional cage-like MOF, SrCu(HC 3 N 3 O 3 ) 2 , constructed by a polydentate cyanurate ligand and two kinds of different metal nodes. A high ratio of coordination sites in organic ligands, specific coordination of strong acid with a strong base and weak acid with a weak base and double independent completed coordination networks endow SrCu(HC 3 N 3 O 3 ) 2 with outstanding thermal stability (up to 300 °C) and acid/alkali resistance (pH = 2-14). Moreover, SrCu(HC 3 N 3 O 3 ) 2 possesses the highest porosity up to 36.7% among cyanuric acid-based MOF materials and exhibits differentiated adsorption of C 3 H 4 (63 cm 3 g -1 ) and C 3 H 6 (51 cm 3 g -1 ). The breakthrough experiment further verified that efficient C 3 H 4 /C 3 H 6 separation can be achieved under dynamic conditions by SrCu(HC 3 N 3 O 3 ) 2 .

Metal thiophosphates have outstanding properties for the generation of mid-infrared coherent light and are an emerging nonlinear optical material system. In this study, a new non-centrosymmetric (NCS) quaternary alkaline-earth metal thiophosphate, SrAgPS 4 , was obtained via a high-temperature solid-state method. The new compound crystallizes in the NCS Ama 2 (No. 40) space group and features two-dimensional [AgPS 4 ] 2- layers consisting of alternately connected [PS 4 ] and [AgS 4 ] tetrahedra. SrAgPS 4 exhibits a strong phase-matched second harmonic generation response (1.10 × AgGaS 2 at 2100 nm) and a large band gap (2.97 eV). In addition, theoretical calculations reveal the intrinsic relationship between the electronic structure and optical properties. This work enriches and greatly promotes the research on infrared nonlinear optical materials based on thiophosphates.

Inorganic metal chalcohalides are significant semiconductive materials for photovoltaics, photodetetion and infrared optics. Thus it is considerably rewarding to develop a new synthetic strategy to provide more degrees of freedom for atomic coordination to tune the optical and electronic properties of metal chalcohalides. In this work, the mixed-anion strategy is performed to synthesize two new metal chalcohalides Cs 2 InPS 4 X 2 (X = Cl, Br) with mixed-anion structure by the reaction of InPS 4 and CsX. Single-crystal X-ray diffraction analysis shows that they are isostructural and crystallize in the centrosymmetric space group P 2 1 / n , consisting of zero-dimensional structure [In 2 P 2 S 8 X 4 ] 4- (X = Cl, Br) built from tetrahedral [PS 4 ] 3- and octahedral [InS 4 X 2 ] 7- (X = Cl, Br) through edge-sharing, with Cs cations filling in intervening voids. The UV-vis-NIR diffuse reflectance spectroscopy measurement reveals that Cs 2 InPS 4 Cl 2 and Cs 2 InPS 4 Br 2 exhibit large optical bandgaps of 3.21 eV and 3.12 eV, respectively. The electronic structure calculations show that the bandgap mainly originates from the [InS 4 X 2 ] 7- (X = Cl, Br) mixed-anion groups. First-principles calculations indicate that the birefringence of Cs 2 InPS 4 Cl 2 and Cs 2 InPS 4 Br 2 is ∼0.08 and ∼0.05 at 2090 nm, respectively. Furthermore, thermal analysis reveals that the Cs 2 InPS 4 X 2 (X = Cl, Br) are thermostable up to 400 °C. This discovery enriches the structural diversity of inorganic chalcohalides and provides an insight for the exploration of new semiconductive materials.