Synthesis and investigation of a new coordination compound: Ammonium octafluoridoindate-zirconate heptahydrate NH4InZrF8·7H2O

Abstract

Abstract The synthesis and complex studies (XRD, DTA, IR, and NMR (1H, 19F, including 19F MAS NMR)) of a new coordination compound of the composition NH4InZrF8·7H2O have been performed. The structure of NH4InZrF8·7H2O is built from infinite chains [ ZrF 8 In ( H 2 O ) 4 ] 1 − ∞ 1 linked to each other by hydrogen bonds O H⋯F into layers alternating with those consisting of ammonium cations and crystallization H2O molecules. Dehydration of the compound NH4InZrF8·7H2O proceeds stepwise in the temperature ranges 323–403 K and 403–503 K with formation of NH4InZrF8·H2O and NH4InZrF8, respectively. Anhydrous compound and monohydrate are characterized with the ability of water absorption from air. Juxtaposition of the 19F MAS NMR spectra of crystal hydrates NH4InZrF8·7H2O and NH4InZrF8·H2O allowed concluding that the monohydrate formation was accompanied by restructuring and formation of a complex anion containing, aside from the terminal Zr Ft bonds, bonds of the same type (In Ft) that were absent in the initial compound anion.