NaSC2H: A First Crystalline Compound with a −SC2H Anion, an Isolobal Variant of Ubiquitous −SCN
Year: 2025
Type: article
Abstract: NaC2H is reacted with elemental sulfur in liquid ammonia, yielding crystalline NaSC2H as a yellow‐brownish powder. It contains the anion −SC2H, an isolobal variant of the well‐known −SCN, thiocyanate. Its existence is confirmed by infrared (IR) and Raman spectroscopy, and its crystal structure is solved and refined using synchrotron powder diffraction data (Swiss Norwegian Beam Line, European Synchrotron/Grenoble). NaSC2H crystallizes in a cubic unit cell with a = 6.8507(3) Å (295 K; 100 K: 6.8024(2) Å), analogous to the previously reported NaSeC2H. The best Rietveld fit is obtained in a pyrite‐type structure (Pa, Z = 4) with a static orientation disorder of the −SC2H anion across two positions. No phase transition or ordering of the anions is observed down to 100 K. Upon heating or after several days at room temperature, NaSC2H releases C2H2, as shown by thermal analysis (differential scanning calorimetry/thermogravimetric analysis) and gas chromatography. In contrast to NaSeC2H, no cubic intermediate with the postulated composition Na2S2C2 is formed, but Na2S is found in the residue after heating to 200 °C. Possible decomposition reactions for NaSC2H are discussed.
Authors: Marc Hetzert, Lisa Körtgen, Uwe Ruschewitz
Institution: University of Cologne
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,960
Awards: G2987550605, G691037175
OpenAlex ID: W4410723135