The crystal structures of some open-chained trichlorophosphazenes, the , NPCb groups attached to carbon, were determined at low temperature (90K, 100K), and the structures were compared in order to show the conformational variability of these compounds. This investigation comprises the structures of the : cations in [C1-C(NPC1 3 ) 2 ]PCU and in [CH 3 -C(NPCl3)2]SbCl 6) and the molecular structures of 2,2,4-trichloro-6-trichlorophosphazeno-l,3,5,2X 5 -triazaphosphorine, C2CI6N4P2, and of a triclinic and a monoclinic modification.of 2,4,6-tris(trichloro-' phosphazeno)-l,3,5-triazine, C3CI9N6P3.