Ammoniumbis(hydroxylammonium) Pentafluoridooxidovanadate(IV): Synthesis and Characterisation of a New Fluorovanadate

Brina Dojer,*,1 Matjaž Kristl,1 Zvonko Jagličić,3 Miha Drofenik1,2 and Anton Meden4

1University of Maribor, Faculty of Chemistry and Chemical Engineering, Smetanova 17, SI-2000 Maribor, Slovenia
2Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
3Institute of Mathematics, Physics and Mechanics and Faculty of Civil and Geodetic Engineering, University of Ljubljana, Slovenia
4University of Ljubljana, Faculty of Chemistry and Chemical Technology, Aškerčeva 5, SI-1000 Ljubljana, Slovenia
* Corresponding author: E-mail: brina.dojer@uni-mb.si

Abstract
Turquoise crystals of a new hydroxylammonium compound with the formula NH4(NH3OH)2[VOF5] have been synthesized by the reaction of solid NH3OHF and the aqueous solution of vanadium in HF. The compound crystallizes monoclinic, P21/n, with cell parameters: a = 10.5658(2) Å, b = 6.6143(1) Å, c = 11.6618(2) Å, β= 96.282(1). Magnetic susceptibility was measured using a SQUID device over a temperature range 2–300 K at magnetic field 103 Oe giving the result µeff = 1.65 BM. The thermal decomposition was studied by TG and DSC analysis. NH4(NH3OH)2[OF5V] decomposes above 354 K in three steps, obtaining NH4VOF3 after the first step and V2O5 as the final residue.

Keywords: Hydroxylammonium fluorovanadates, X-ray powder diffraction, X-ray structure determination, thermal
analysis