Molecular structure of aminoguanidine sulfate monohydrate

The single crystal of aminoguanidine sulfate monohydrate[(AG)2SO4&middotH2O] is obtained and its structure is determined by X-ray diffraction analysis. The compound crystallizes in orthorhombic system with space group Pnma and the empirical formula C2H16N8O5S. The unit cell parameters are as follows: a=0.6759 (2) nm, b=1.4131 (5) nm, c=1.1650 (4) nm, V=1.1128 (6) nm3, Z=4, Dc=1.578 g/cm3, F (000)=560, s=1.069, μ(MoKα)=0.318 mm-1. The final R and wR are 0.0312 and 0.0833, respectively. The title compound is an ionic compound and its structure unit consists of two aminoguanidium cations, one sulfate anion and one crystal water molecule, which are interconnected by electrostatic forces and hydrogen bonds into net structure, making the title compound very stable. Under a linear heating rate, the thermal decomposition processes of (AG)2SO4&middotH2O have one endothermal dehydration stage, one melting process and one exothermic decomposition stage at 50-400°C, and can evolve abundant gas products.