Structure of 1,cis-3,cis-5,trans-7-tetrachloro-1,3,5,7-tetrakis(dimethylamino) cyclotetraphosphazene

Abstract

Crystals of the title compound, one of the non-geminally substituted tetrakis(dimethylamino)chlorotetraphosphazenes, are monoclinic with a= 36.473(13), b= 9.360(3), c= 13.684(3)Å, β= 105.04(2)°, space group C2/c,Z= 8. Atomic positions have been determined by Patterson and Fourier methods from X-ray diffractometer data and refined by least squares to R 0.11 for 1 489 reflections. One feature of the structure is the inequality of the ring-bond distances at N(6). The structure determination confirms the cis,cis,cis,trans orientation of the dimethylamino-groups which leads to a mixed ‘crown-saddle’ conformation for the P₄N₄ ring.