Hydroxylammonium fluorosilicates

A new hydroxylammonium compound (NH3OH)2SiF6, has been synthesized by the addition of solid NH3OHF to an aqueous solution of H2SiF6. The compound was characterized by chemical analysis and X-ray powder diffraction, the thermal decomposition was studied by thermal analysis and mass spectrometry. (NH3OH)2SiF6 crystallizes triclinic. Four endothermic peaks have been observed on the DSC curve, the decomposition products are HF, NH3OHF and SiF4 and the weight loss at 500°C is nearly 100%.