Crystal and molecular structure of tetramethylformamidinium phosphonic anhydride, [(Me2N)2CPO2]2O

Abstract

Crystals of the title compound are monoclinic, space group C2/c with a= 11·170, b= 10·613, c= 14·077 Å, β= 103° 24′, Z= 4. Diffractometer data for 2092 planes were used to solve the structure by direct methods and were refined by least-squares to a final R of 0·065 (for 2092 planes). The molecule possesses a two-fold crystallographic symmetry axis passing through the central oxygen atom. Important bond lengths are P–O(terminal) 1·469(2), P–O(bridge)1·619(2), P–C 1·880(2), N–C(sp²) 1·331(3), N–C(sp³) 1·463(4)Å; P–O–P is 125·9(1)°