37488-75-8Relevant articles and documents
Synthesis, crystal structure and properties of K2Ta 2S10: A novel ternary tantalum polysulfide with TaS 8 polyhedra forming infinite anionic chains
Wu, Yuandong,Naether, Christian,Bensch, Wolfgang
, p. 1569 - 1574 (2005)
The new ternary alkali tantalum polysulfide K2Ta 2S10 has been synthesized by reacting TaS2 with an in situ formed melt of K2S3 and S at 773 K. The compound crystallizes with four formula units in the monoclinic space group P21/n (No. 14) with lattice parameters of a=14.9989(13)A,b=6. 4183(4)A,c=15.1365(13)A,β=117.629(9)°. The structure contains two different zigzag chain anions [TaS5]-, running parallel to the crystallographic b-axis separated by potassium cations. The two crystallographically independent tantalum atoms are in a distorted bi-capped trigonal prismatic environment of eight sulfur atoms which was never observed before. The TaS8 polyhedra share three S atoms on each side to form the anionic chains. The compound was characterized with FIR and Raman spectroscopy.
Tartar, H. V.
, p. 1741 - 1747 (1913)
Synthesis and modulated crystal structure of KBaNbS4
Wu, Yuandong,Doert, Thomas,Bensch, Wolfgang
, p. 3019 - 3024 (2005)
Single crystals of KBaNbS4 have been prepared by the reaction of Nb with an in situ formed melt of K2S3, BaS, and S at 500°C. Satellite reflections observed in X-ray diffraction experiments of these crystals indicate the presence of a one-dimensional lattice distortion. The modulated structure has been solved and refined from X-ray data using the superspace group approach. KBaNbS4 can be described in the (3 + 1)-dimensional superspace group Pnma(α00)0s0 with lattice parameters a = 9.187(1), b = 7.001(1), and c = 12.494(1)A and a modulation vector q = (0, 0.629(1), 0). In the structure the NbS4 tetrahedra are stacked along the a axis and show a slight tilting against each other. The K+ and Ba2+ ions follow this tilting, both are slightly shifted from their positions in the average structure. The modulation does not lead to a significant change in the coordination spheres of the metal atoms. The small effects of the modulation correspond to the relatively weak intensities of the satellite reflections. Results of temperature dependent X-ray investigations indicate that K+ librates at higher temperatures and the surrounding S2- anions follow this motion. With decreasing temperature the libration of K+ is reduced and the coordination geometry freezes under formation of an incommensurate modulation. The heavier Ba and Nb atoms are also affected by positional modulation of the substructure and accommodate to their environment.
KBiMS4 (M=Si, Ge): Synthesis, structure, and electronic structure
Mei, Dajiang,Lin, Zheshuai,Bai, Lei,Yao, Jiyong,Fu, Peizhen,Wu, Yicheng
, p. 1640 - 1644 (2010)
Two new bismuth sulfides KBiSiS4 and KBiGeS4 have been synthesized by means of the reactive flux method. They adopt the RbBiSiS4 structure type and crystallize in space group P21/c of the monoclinic system. The structure consists of 2∞[Bi M S4-] (M=Si, Ge) layers separated by bicapped trigonal-prismatically coordinated K atoms. The M atom is tetrahedrally coordinated to four S atoms and the Bi atom is coordinated to a distorted monocapped trigonal prism of seven S atoms. The optical band gap of 2.25(2) eV for KBiSiS4 was deduced from the diffuse reflectance spectrum. From a band structure calculation, the optical absorption for KBiSiS4 originates from the 2∞[BiSiS4-] layer. The Si 3p orbitals, Bi 6p orbitals, and S 3p orbitals are highly hybridized near the Fermi level. The orbitals of K have no contributions on both the upper of valence band and the bottom of conduction band.
Syntheses, crystal structures and spectroscopic properties of Ag2Nb[P2S6][S2] and KAg2[PS4]
Wu, Yuandong,Bensch, Wolfgang
, p. 471 - 478 (2009)
Ag2Nb[P2S6][S2] (1) was obtained from the direct solid state reaction of Ag, Nb, P2S5 and S at 500 °C. KAg2[PS4] (2) was prepared from the reaction of K2Ss
Synthesis and crystal structure of new ternary chalcogenides of group IV metals: K2ZrS4, Rb2ZrS4, and Rb2HfS4
Rumpf,Bensch
, p. 695 - 698 (2000)
The new ternary one-dimensional chain compounds K2ZrS4, Rb2ZrS4 and Rb2HfS4 were prepared at 350 °C by reacting A2S3 and S with elemental M (A = K, Rb; M = Zr, Hf). They are isostructural, crystallizing in the orthorhombic space group Pbca with Z = 8. The M atoms are in a distorted octahedral environment of four S2- anions and one S22- unit. The structure consists of infinite anionic chains comprised of edge-sharing MS6 octahedra running parallel to the [001] direction separated by the alkali metal cations. The composition of the chain may be formulated as 1∞[MS4/2(S2)2-]. The two crystallographically independent alkali cations are in eight-and ninefold coordination of S atoms.
Na2GaS2Cl: A new sodium-rich chalcohalide with two-dimensional [GaS2]∞layers and wide interlayer space
Li, Xiaoshuang,Liang, Fei,Liu, Tianpeng,Li, Haifeng
, p. 11167 - 11172 (2021/08/25)
By introducing halogens to the A/Ga/Q (A = Na, K; Q = S, Se) system, one new chalcohalide namely Na2GaS2Cl was successfully obtained. It crystallizes in the orthorhombic space group Cmcm (63). Na2GaS2Cl has a layered structure consisting of two dimensional [GaS2]∞ layers which are stacked in face to face and back to back arrays and separated by Na+ and Cl- ions. Interestingly, supertetrahedral building units [Ga4S10] (T2) which are rarely found in metal chalcogenides and metal chalcohalides are formed in this structure. Moreover, the distances of two adjacent layers are around four times larger than the ionic radius of the Na+ ion, which is very likely to provide a perfect environment for the storage and migration of Na+ ions. In particular, the volume concentration of the Na+ cations in this compound is as high as 1.54 × 1022 cm-3. The UV-vis-NIR spectroscopy measurement reveals that the optical band gap of this title compound is 3.06 eV. The electronic structural calculations on Na2GaS2Cl show that the band gap is mainly determined by the [GaS4] groups and Na-Cl ionic bonding.
Understanding fluxes as media for directed synthesis: In situ local structure of molten potassium polysulfides
Shoemaker, Daniel P.,Chung, Duck Young,Mitchell,Bray, Travis H.,Soderholm,Chupas, Peter J.,Kanatzidis, Mercouri G.
, p. 9456 - 9463 (2012/07/14)
Rational exploratory synthesis of new materials requires routes to discover novel phases and systematic methods to tailor their structures and properties. Synthetic reactions in molten fluxes have proven to be an excellent route to new inorganic materials because they promote diffusion and can serve as an additional reactant, but little is known about the mechanisms of compound formation, crystal precipitation, or behavior of fluxes themselves at conditions relevant to synthesis. In this study we examine the properties of a salt flux system that has proven extremely fertile for growth of new materials: the potassium polysulfides spanning K2S3 and K 2S5, which melt between 302 and 206 °C. We present in situ Raman spectroscopy of melts between K2S3 and K 2S5 and find strong coupling between n in K 2Sn and the molten local structure, implying that the Sn2- chains in the crystalline state are mirrored in the melt. In any reactive flux system, K2Sn included, a signature of changing species in the melt implies that their evolution during a reaction can be characterized and eventually controlled for selective formation of compounds. We use in situ X-ray total scattering to obtain the pair distribution function of molten K2S5 and model the length of Sn2- chains in the melt using reverse Monte Carlo simulations. Combining in situ Raman and total scattering provides a path to understanding the behavior of reactive media and should be broadly applied for more informed, targeted synthesis of compounds in a wide variety of inorganic fluxes.
