The title compd. is orthorhombic, space group Pbca, with a 21.8632(9), b 9.2726(5), c 7.7450(7) .ANG.; d. (calcd.) = 1.271 for Z = 8. Final R = 0.052 for 853 reflections. At. coordinates are given. The compd. has a syn-syn conformation with a planar environment for the N atoms. The interplanar angle between the P group and the urea skeleton is .apprx.30 Deg. The crystal structure is stabilized by the formation of intermol. N-H...O hydrogen bonds with an H...O distance of 2.12 .ANG. (mean value) and an N-H...O angle of 156 Deg (mean value).