A wide variety of isostructural phases of the NZP family, AM′3+M″4+ P3O12, have been synthesized. Some of these phases are reported for the first time. Characterizations by IR, EPR, and UV-visible spectroscopic methods are presented. DC magnetic susceptibility measurements on selected phases show antiferromagnetic ordering of AZrFeP3O12 (A = Sr, Ba) phases. © 1994 Academic Press, Inc.