Some mixed-valent praseodymium and terbium iodates

The reactions between aqueous iodic acid and some lanthanide oxides have been investigated. TbO 2 and Tb 4 O 7 both yield a compound Tb IV O 2 ·2 Tb III ( IO 3 ) 3 · nH 2 O . Pr 6 O 11 and PrO 2 also yield mixed oxidation state phases but no reproducible compounds were obtained. Infrared and u.v./visible spectra and magnetic moment measurements are reported.