Hydrogen bis(tetraphenylimidodophosphonic acid) triiodide

In the crystal structure of the title compound, [(C24H21NO2P2)2H]+.I3 - , the triiodide anion is linear, sitting across a centre of symmetry, with I—I distances of 2.9130 (6) A ˚ . The [H{(OPPh2)2NH}2]+ cation is formed by two symmetry-related molecules of tetraphenylimidodiphosphinic acid, (OPPh2)2NH, exbiting for the O—P—N—P—O skeleton an anti conformation [code (-,+)/(+,-)] with an angular P—N—P fragment. The charge is determined by a single proton shared by these two molecules, disordered across a centre of symmetry and forming an O—H...O hydrogen bond