The cover picture shows an illustration of the paper title, in which we displayed the intention to shift our research interests from oxido‐ to sulfidotungstates. Combined with the other ingredients (sodium cations and water molecules), we obtained singles crystals (see figure at bottom right) of Na2[WS4]⋅4H2O, of which an excerpt of the layered structure is shown. The background is a self‐taken photograph of crystallized sulfur at Lassen Volcanic National Park in California, USA. Furthermore, the picture also contains an “easter egg” related to Thomas Schleid (DOI: 10.1002/zaac.202200270).
An attempt to synthesize a holmium sulfidotungstate using potassium polysulfides as reactive flux resulted in orange single crystals of K2[WS4], isotypic to K2[MoS4] (orthorhombic; Pnma; a=935.10(3), b=694.22(2), c=1221.85(4) pm; Z=4). A similar attempt to obtain a neodymium sulfidotungstate with sodium polysulfide yielded a violet substance, which underwent hydrolysis yielding orange‐yellow single crystals of Na2[WS4] ⋅ 4 H2O (monoclinic, C2/c, a=1098.08(4), b=904.46(3), c=1144.27(4) pm, β=101.577(3)°, Z=4). Further attempts to synthesize these products deliberately as single phase materials only proved to be successful for K2[WS4] but not for Na2[WS4] ⋅ 4 H2O. Both compounds contain non‐condensed [WS4]2− tetrahedra, which surround the alkali metal cations with coordination numbers of nine and eight in K2[WS4]. In Na2[WS4] ⋅ 4 H2O, the sodium cations are coordinated by two sulfide anions plus four water molecules, resulting in a coordination number of six. Besides crystal structure determination, infrared and single crystal Raman spectra were collected and the optical band gap of K2[WS4] was determined.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.