The reactions of some geminal phenylchlorocyclotriphosphazatrienes, N₃P₃Ph₂Cl₄ and N₃P₃Ph₄Cl₂, with alkoxide ions have been investigated. The expected geminal alkoxy-derivatives, N₃P₃Ph₂(OR)₄ and N₃P₃Ph₄(OR)₂, have been isolated together with variable yields of by-products in which one alkoxy-group of the alkoxyphenylcyclo-triphosphazatriene has been replaced by the elements of a hydroxy group to yield “cyclotriphosphazadienes”. Treatment of the geminal diethoxytetraphenyl- and of hexamethoxy-cyclotriphosphazatriene with anhydrous hydrogen chloride led to a “cyclotriphosphazadiene” and a “cyclotriphosphazene,” respectively. 2,4,6-Tribenzyloxy-1,3,5-tribenzyl-2,4,6-trioxocyclotriphosphazane has been O-debenzylated by treatment with sodium iodide in acetone. Structures for these partially “hydrolysed” products are suggested on the evidence of their infrared and ¹H nuclear magnetic resonance spectra, and their mode of formation is discussed, comparisons being drawn with the products of hydrolysis of chloro- and alkoxy-phosphazenes.