Synthesis and Stability of Ammonium Selenocyanate [NH 4 ][SeCN] and Its Reactivity toward Ag[SeCN].

[NH 4 ][SeCN] and Ag[SeCN] were synthesized by salt metathesis starting from the respective chlorides and K[SeCN]. Both products were fully characterized by single-crystal and powder X-ray diffraction, differential scanning calorimetry-thermogravimetric analysis (DSC-TGA), and solid-state IR and Raman spectroscopy. Quantum-mechanical calculations allowed for detailed assignment and interpretation of vibrational spectra. For dissolved [NH 4 ][SeCN], nuclear magnetic resonance spectra were collected. High-temperature powder X-ray diffraction (HT-PXRD) allowed for the analysis of the thermal behavior of solid [NH 4 ][SeCN]. Furthermore, the reaction of [NH 4 ][SeCN] with Ag[SeCN] leads to the formation of the ternary salts [NH 4 ][Ag(SeCN) 2 ] and [NH 4 ] 3 [Ag(SeCN) 4 ]. The structures of the latter were determined from single-crystal X-ray diffraction (SC-XRD) data, and bulk analysis was performed by Rietveld refinement, Raman spectroscopy, and elemental analysis.