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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]

Abstract: The alkaline-earth uranium chalcogenide Ba2Cu2US5 was obtained in a two-step reaction from BaS, Cu2S, and US2. Ba2Cu2US5 crystallizes in a new structure type in space group C2/m of the monoclinic system with two formula units in a cell of dimensions a=13.606(3)Å, b=4.0825(8)Å, c=9.3217(19)Å, and β=116.32(3)° (153K). The structure consists of layers separated by Ba atoms in bicapped trigonal-prismatic coordination. The two-dimensional layer is built from US6 octahedra and CuS4 tetrahedra. The connectivity of the MSn polyhedra within the layer in the [001] direction is oct tet tet oct tet tet. A μ eff value of 2.69(2) μ B/U was obtained from the magnetic susceptibility data. No magnetic transition was observed for Ba2Cu2US5 down to 2K. [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]

Three new diamond-like compounds with the formula of I2−II−IV−VI4 (I=Cu; II=Mg; IV=Si, Ge; VI=S, Se) have been synthesized via traditional high-temperature solid-state reactions and structurally characterized by single crystal X-ray diffraction analysis. All the three compounds crystallize in the space group Pmn21 in the wurtzite-type superstructure with a=7.563(4), b=6.448(3), c=6.179(3)Å, Z=2 for Cu2MgSiS4 (1); a=7.953(5), b=6.797(4), c=6.507(4)Å, Z=2 for Cu2MgGeS4 (2); a=7.638(4), b=6.515(4), c=6.225(3)Å, Z=2 for Cu2MgSiSe4 (3). All atoms in these compounds are tetrahedrally coordinated. Optical diffuse reflectance UV/Vis/NIR spectra indicate that compounds 1 and 2 have the band gaps of 3.20 and 2.36eV, respectively. Electronic structure calculations using the CASTEP code indicate that they are all direct band gap compounds. [ABSTRACT FROM AUTHOR]

Mid-far infrared (IR) non-linear optical (NLO) materials are of great importance in military and civil fields. However, commercial IR-NLO crystals (such as AgGaS 2 , AgGaSe 2 and ZnGeP 2 ) do not currently satisfy the requirements of large second-harmonic generation (SHG) and high laser induced damage thresholds (LIDTs), which seriously limits their practical applications. Herein, we have developed a new series of salt-inclusion chalcogenides, [A 3 X][Ga 3 PS 8 ] (A = K, Rb; X = Cl, Br), which are constructed from alternate stacking of adamantane-like [Ga 3 PS 10 ] 6- cluster layers and cationic [A 3 X] 2+ salt layers. Importantly, they display both large SHG responses of several-fold and high LIDTs for dozens of times that of commercial AgGaS 2 , which exhibit the highest LIDTs among the reported IR-NLO materials with a larger SHG conversion efficiency than that of AgGaS 2 . These properties together with wide transparent region, type I phase-matching features and congruent-melting behaviors indicate they are promising IR-NLO materials.

The title compound, [[Cu(4)(C(3)H(4)NS(2))(4)] x 2H(2)O](n), was produced by diffusing a solution of 2-mercaptothiazoline in tetrahydrofuran into a solution of CuCl in CH(3)CN at room temperature. The structure is characterized by self-assembled one-dimensional chains that are condensed from butterfly-like [Cu(C(3)H(4)NS(2))](4) tetrameric units via double S-bridging at opposite ends. The Cu[bond]Cu distances within the Cu(4) butterfly cluster are in the range 2.7103 (10)-2.9764 (10) A, while the shortest Cu...Cu intercluster distance is 3.468 (1) A, much longer than the sum of the van der Waals radii.