Monoammonium Trimetaphosphimate (NH₄)H₂(PO₂NH)₃

Abstract

Trimetaphosphimates show a rich structural variability in both cation coordination and anion arrangement. They are precursors for crystalline, as well as amorphous oxonitridophosphates. The ammonium trimetaphosphimate (NH4)H2(PO2NH)3 is formed during the decomposition of the corresponding acid in solution. The monoclinic crystal structure of the monoammonium salt was elucidated by single crystal X-ray diffraction using synchrotron radiation. The trimetaphosphimate monoanions exhibit a twist conformation and form crankshaft-like stacks along [100], which have so far only been observed in (NH4)3(PO2NH)3·H2O and Ag3(PO2NH)3. (NH4)H2(PO2NH)3 decomposes at 170 °C, forming a poorly crystalline phase. Therefore, it is a model system and possible precursor for the synthesis of oxonitridophosphates.

Keywords

• trimetaphosphimate
• single-crystal structure determination
• thermal decomposition
• hydrogen bonding
• packing of rings