Materials Data on H12C4N2O9 by Materials Project

Abstract

(NH4)2(HC2O4)2H2O crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of eight ammonium molecules, four water molecules, and eight HC2O4 clusters. In each HC2O4 cluster, there are two inequivalent C3+ sites. In the first C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.26 Å) and one longer (1.28 Å) C–O bond length. In the second C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.23 Å) and one longer (1.32 Å) C–O bond length. H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.04 Å) and one longer (1.54 Å) H–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C3+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C3+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one C3+ and one H1+ atom. In the fourth O2- site, O2- is bonded in a water-like geometry to one C3+ and one H1+ atom.