The oxyphosphates Ln(3)PO(7) (Ln = La-Er) were prepared by the solid-s
tate reaction technique, and single crystals of La3PO7 were grown. The
materials were characterized by x-ray diffraction and IR spectroscopy
. All of the compounds are shown to be isostructural (sp. gr. Cm). The
assignment of IR absorption and Raman bands and the lattice parameter
s of the oxyphosphates are presented.