The non-isotypic pair CsCe[SiS4] and CsCe[SiSe4]: A structural comparison

KBiMS4 (M=Si, Ge): Synthesis, structure, and electronic structure

“…The structure of the 1 2 ½BiSiS À 4 layer in the KBiSiS 4 is similar to that of 1 2 ½BiSiS À 4 layer in CsBiSiS 4 shown in Fig. 4 and the structure of the 1 2 ½LnMS À 4 layer in the ALnMS 4 (A ¼alkali metal, Ln ¼rare earth; M ¼Si, Ge) series of compounds [28][29][30][31][32][33][34][35][36][37][38][39]. The differences between the structures of KBiSiS 4 and CsBiSiS 4 (Fig.…”

“…In the ALnMS 4 (A¼alkali metal, Ln ¼rare earth; M¼Si, Ge) series of compounds, the two common structure types are represented by KLaGeS 4 (space group P2 1 ) [33] and CsSmGeS 4 (space group P2 1 2 1 2 1 ), [34] while b-KCeSiS 4 (space group P2 1 /m) [36] and CsCeSiS 4 (space group Pnma) [39] adopt the other two less common structure types. In contrast to KBiSiS 4 , the ALnMS 4 compound exhibit much smaller differences in the Ln-S bond lengths within the LnS n (n ¼7, 8) polyhedra.…”

Oxygen out, sulfur in: The alkali metal sulfidotungstates K2[WS4] and novel Na2[WS4] ⋅ 4 H2O

“…First, the ligand‐to‐metal charge‐transfer (LMCT), present in complex sulfidotungstate entities is strongly shifted towards regions of lower energies, compared to the respective oxidotungstates, [9] which can easily be seen by the yellow to red colors of the materials containing sulfidotungstate entities, in contrast to the mostly colorless oxidotungstate ones. Second, other than many sulfidoanions, such as sulfidophosphates, [10] ‐silicates, [11] etc., [WS 4 ] 2− units do not undergo complete or superficial hydrolysis, thus remaining stable to atmospheric conditions. In attempts to remedy the lack of rare‐earth metal sulfidotungstates in solid‐state reactions utilizing potassium and sodium polysulfides, such as K 2 S 3 [12] or Na 2 S 6 [13] as reactive flux, respectively, the title compounds emerged as by‐products.…”

Molten Alkali Halide Flux Growth of an Extensive Family of Noncentrosymmetric Rare Earth Sulfides: Structure and Magnetic and Optical (SHG) Properties

“…11 The most common main group chalcogenide building block in these compounds is the tetrahedral TQ 4 building unit (T = Si, Ge; Q = S, Se), and in the series of structures featuring the TQ 4 building unit, the quaternary compounds with the general formula ALnTQ 4 (A = alkali metal; Ln = rare earth; T = Si, Ge; Q = S, Se) constitute one of the most prevalent structure types that crystallize in numerous structural variations. 12,13 Specifically, these compounds have the propensity to crystallize in a variety of space groups ranging from the noncentrosymmetric space groups, P2 1 and P2 1 2 1 2 1 , to the centrosymmetric space groups, P2 1 /c and Pnma. 14,15 Almost all of the ALnTQ 4 phases reported to date were prepared from molten alkali polychalcogenide fluxes, A 2 Q n (A = alkali metal, Q = S, Se), which function simultaneously as the high-temperature flux and the alkali metal source.…”