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Three new ternary rare-earth zirconium chalcogenides, Ce 2 ZrSe 5 ( 1 ), Pr 2 ZrSe 5 ( 2 ) and Nd 2 ZrSe 5 ( 3 ), have been synthesized by a facile solid-state route with boron as the reducing reagent. They crystallize in the space group Pnma of the orthorhombic system, belonging to the U 3 Se 5 structure type. Their 3-D structures are constructed by parallel polyanionic {[ZrSe 5 ] 6– } n chains and LnSe 8 bicapped trigonal prisms. The magnetic susceptibilities' data indicate their antiferromagnetic-like behavior without magnetic order down to 2 K. The structural relationships among several similar structures are discussed, together with the lanthanide contraction in the Ln 2 ZrSe 5 system. [ABSTRACT FROM AUTHOR]

Abstract: In our investigation of non-centrosymmetric rare earth sulfides in the La3AgSnS7/KBr, LaAlGeS5/NaBr, HoAlGeS5/KBr, ErAlGeS5/NaBr, Er3AgGeS7/KBr and La3NaSnS7/NaBr systems, five compounds belonging to the R6B2C2Q14 family have been obtained. These compounds crystallize in the P63 space group, and the crystal data are as follows—La3AgSnS7: a =10.3780(15)Å, c =5.9900(12)Å, Z =2; La3Ge0.25GeS7: a =10.2970(15)Å, c =5.8120(12)Å, Z =2; Ho3Ge0.272(10)GeS7: a =9.6480(14)Å, c =5.7920(12)Å, Z =2; Er3Ge0.330(10)GeS7: a =9.5930(14)Å, c =5.8490(12)Å, Z =2; La3Sn0.25SnS7: a =10.2770(15)Å, c =6.0030(12)Å, Z =2. Single-crystal analysis indicated that the crystal structures consist of three types of building block: LnS n , MS4, and AgS3 (for La3AgSnS7) or MS6 units (for Ln3M x MS7, Ln=La, Ho, Er; M=Ge, Sn; 1/4≤ x ≤1/2), as any other compounds belonging to the R6B2C2Q14 family. Ln3M x MS7 (Ln=La, Ho, Er; M=Ge, Sn; 1/4≤ x ≤1/2) are deficient compounds with the B sites occupied partly by M(II), and/or M(IV). [Copyright &y& Elsevier]

• A new phase β -PbGa 2 S 4 that crystallizes in a non-centrosymmetric space group of Pna 2 1 was synthesized. • The structure of β -PbGa 2 S 4 is composed of a framework [Ga 8 S 16 ]8− with hexagonal voids filled by Pb atoms. • β -PbGa 2 S 4 demonstrates moderate phase matching second-harmonic generation response and laser-induced damage threshold. [Display omitted] Nonlinear optical (NLO) crystals can produce tunable lasers through the direct second-harmonic generation (SHG) process, which is of great significance in modern laser technology. Herein, a new chalcogenide β -PbGa 2 S 4 (1) crystallized in space group of Pna 2 1 was synthesized via high-temperature solid-state reactions. Compound 1 is composed of a three-dimensional framework [Ga 8 S 16 ]8− with hexagonal voids filled by Pb atoms via covalent Pb–S interactions. Importantly, it exhibits promising NLO performances, such as phase-matchable SHG efficiency (0.6×AgGaS 2 @1200 nm and 0.1×AgGaS 2 @1910 nm), moderate band-gap (2.46 eV), suitable laser-induced damage threshold (3.0×AgGaS 2), and a broad IR transparency window (0.5–25.0 µm). SHG response of 1 is mainly attributable to the occupied S–3p and Ga–4p states and unoccupied S–3p and Pb–6p states. [ABSTRACT FROM AUTHOR]

A new compound NaIn 3 S 5 has been obtained in the CaS–In 2 S 3 /NaBr system via a reactive flux method. NaIn 3 S 5 crystallizes in the orthorhombic space group Pbam (No. 55) with a = 12.4963(8) Å, b = 16.0811(10) Å, c = 3.8041(2) Å, and Z = 4. The NaIn 3 S 5 structure is characterized by a three dimensional framework consisting of interconnected tripartite-octahedral [ In 3 S 8 ] ∞ 1 infinite chains, with Na + cations residing in the one-dimensional channels along the c direction defined by S(1), S(2), S(3) and S(4) atoms. The optical reflectance measurement shows a band gap of 2.18 eV for NaIn 3 S 5 . Electronic structure calculation by the CASTEP code not only indicates that NaIn 3 S 5 is an indirect band gap semiconductor, but also explains why its experimental band gap is close to that of β-In 2 S 3 . [ABSTRACT FROM AUTHOR]

• [Rb 4 Cl][Cd 11 In 9 S 26 ] was a novel noncentrosymmetric salt-inclusion Chalcogenide. • It presents a distinctive [Cd 11 In 9 S 26 ]3 − framework constructed by pseudo-T2-Cd 3 InS 10 and T2-CdIn 3 S 10 supertetrahedra. • It shows decent phase-matchable SHG response, moderate band gap and high LIDT. [Display omitted] Salt-inclusion chalcogenide is a promising infrared (IR) nonlinear optical (NLO) system for its potential in mitigating the incompatibility between second harmonic generation (SHG) efficiency and laser-induced damage threshold (LIDT). Herein, a new noncentrosymmetric salt-inclusion chalcogenide, [Rb 4 Cl][Cd 11 In 9 S 26 ] (1), was prepared by high-temperature solid-state method. It features a distinctive [Cd 11 In 9 S 26 ]3- host framework composing of pseudo-T2-Cd 3 InS 10 and T2-CdIn 3 S 10 supertetrahedra, which are rare in known salt-inclusion chalcogenides. Remarkably, compound 1 exhibits a phase-matchable SHG signal (0.23 times that of benchmark AgGaS 2), which mainly originates from the distorted CdS 4 and InS 4 tetrahedra in the host moiety. Moreover, it possesses moderate band gap (2.32 eV) and high LIDT (4.9 ×AgGaS 2). Such high LIDT may due to its small thermal expansion anisotropy. [ABSTRACT FROM AUTHOR]

Abstract: In our investigation of rare earth sulfides in the AE-RE-Sn-S (AE=alkaline-earth, RE=rare earth) system, three isostructural quaternary sulfides have been obtained. These compounds adopt the Eu5Zr3S12 structure type and crystallize in the P-62m space group (no. 189); the crystal data are as follows: Sr2Y2.67Sn3S12, a =11.600(7)Å, c =3.948(3)Å, Z =1; Ca3La2Sn3S12, a =11.5997(6)Å, c =3.9407(4)Å, Z =1; Ca3Er2Sn3S12, a =11.448(3)Å, c =3.8780(11)Å, Z =1. Single-crystal analysis indicated that the crystal structures consist of three types of building block: RES7, AES6, and SnS6 units. The structure of Sr2Y2.67Sn3S12 is characterized by the trimer-chains along the c direction, which are connected into a 3-dimensional framework by the Sn atoms via S(1), S(2), and S(3), with Sr atoms filling in the channels along the c direction. The optical band gap of 1.45eV for Ca3La2Sn3S12 was deduced from the diffuse reflectance spectrum. [Copyright &y& Elsevier]

Abstract: A new framework compound, [Hg4As2](InBr3.5As0.5) (1), has been prepared by the solid-state reaction of Hg2Br2 with elemental In and As at 450°C. Compound 1 crystallizes in the space group P 63/mmc of the Hexagonal system with two formula units in a cell: a = b =7.7408(6)Å, c =12.5350(19)Å, V =650.47(12)Å3. The crystal structure of 1 features a novel 3D framework, [Hg4As2]2+ with tridymite topology. The optical properties were investigated in terms of the diffuse reflectance and infrared spectra. The electronic band structure along with density of states (DOS) calculated by DFT method indicates that the present compound is semiconductor, and the optical absorption is mainly originated from the charge transitions from Br-4p and As-4p states to Hg-6s and In-5p states. [Copyright &y& Elsevier]

Abstract: High-quality single crystals of RbInS2, CsInS2 were isolated from the halide flux as a major phase of the repeated fusion of CaS and In2S3 followed by slow cooling. RbInS2 and CsInS2 are practically isostructural with KInS2. RbInS2: C2/c, a =11.071(6)Å, b =11.068(1)Å, c =15.610(7)Å, β =100.36(3)°, V =1882(2)Å3, Z =16, d x =3.74g/cm3, R =6.38%, R w =6.42%. CsInS2: C2/c, a =11.197(3)Å, b =11.158(3)Å, c =16.358(4)Å, β =99.92(2)°, V =2013(2)Å3, Z =16, d x =4.12g/cm3, R =5.60%, R w =6.20%. The AInS2 (A=Rb, Cs) structure is characterized by double layers of vertex-sharing [In4S10] units that each consists of four [InS4] polyhedra. The charge-balancing alkali-metal cations are stuffed into the channels created by the packing of these anionic [In4S10] blocks. The optical reflectance measurements show a band gap of 3.3eV for RbInS2 and 3.4eV for CsInS2, suggesting that both are semiconductors. [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]