Crystal and molecular structure of tetramethylformamidiniumphosphonate, [Me2N]2CPO3H

Abstract

Crystals of the title compound, an inner salt [Me₂N]₂CPO₃H, are monoclinic, space-group P2₁/c with a= 8·415 b= 7·719, c= 12·719 Å, β= 91·5°, Z= 4. The structure was solved by direct methods from diffractometer data for 1414 planes, and refined by least squares to a final R of 0·047. The (PO₃H)- group is linked to the central carbon atom of the (Me₂N:C·NMe₂)⁺ group by a P–C bond of 1·890(2)Å. The central carbon atom and the two nitrogen atoms of the formamidinium group all adopt planar configurations.