Solid state reactions of CeO2, ThO2 and PuO2 with ammonium sulphate

Solid state reactions of CeO2, ThO2 and PuO2 with (NH4)(2)SO4 were investig ated by chemical, IR, thermal and X-ray diffraction methods. At 250 degrees C. CeO2,ThO2 and PuO2 formed tetrasulphate compounds i.e.. (NH4)(4)Ce(SO4) (4), (NH4)(4)Th(SO4)(4) and (NH4)(4)PU(SO4)(4). respectively. On further he ating (NH4)(4)Ce(O-4)(4) decomposed to give (NH4)(2)Ce(SO4)(3), (NH4)Ce(SO4 )(2) and Ce-2(SO4)(3); when, cerium undergoes change in oxidation state fro m +4 to +3. The decomposition of(NH4)(4)M(SO4)(4) (M = Th or Pu) led to the formation of(NH2)(2)M(SO4)(3) and M(SO4)(2). Crystal data for solid reacti on products were determined from their X-ray powder diffraction data. Disso lution of the products formed at 350-360 degrees C during the reactions of CeO2,ThO2 and PuO2 with (NH4)(2)SO4 was also investigated. (C) 1999 Publish ed by Elsevier Science B.V. All rights reserved.