Structural changes within the alkaline earth uranyl phosphites.

Three new alkaline earth (AE) uranyl phosphites and one barium uranium(IV) phosphate were synthesized under hydrothermal conditions. The carbonate salts of the AE's were employed both as cation sources and as pH regulators. Despite having very similar formulas and uranyl building units, the Ca(2+), Sr(2+) and Ba(2+) uranyl phosphites have three different extended networks. The calcium compound also contains a Ca(2+)/UO2(2+) mixed cation position. The four structure types will be presented herein with the AE cations generating distinct structural transformations.