Fluoride und Fluorosäuren, IX [1]. Verbindungsbildung im System NOF–HF sowie Kristallstrukturen von NOF·3 HF und NOF·4 HF / Fluorides and Fluoro Acids, IX [1]. Compound Formation in the System NOF–HF and Crystal Structures of NOF·3HF and NOF·4HF

Abstract

The melting diagram of the system NOF-HF (HF-rich region) was studied by DTA and X-ray diffraction. The compounds NOF·3HF and NOF·4HF were confirmed as intermediate solid phases, and formation of a new one, NOF·7HF , was observed. The melting points are -1 °C (dec.), 5 °C and -106 °C (dec.), respectively. The crystal structures of NOF·3HF (space group R3c ,Z = 6 , a = 7.396 Å , c = 12.678 Å) and NOF·4HF (141/a, Z = 4, a = 6.316 Å , c = 13.301 Å) were determined as those of nitrosonium hydrogen fluorides, NO[F(HF)3] and NO[F(HF)4], with orientational disorder of the cations and very strong F-H···F hydrogen bonds in the anions.