Hydrothermal crystallization in the systems La2(CO3)3•6H2O-CaCO3(BaCO3)-R-H2O (R = Na2CO3, K2CO3, NaHCO3, KHCO3, NaCl, NH4Cl, CO(NH2)2)

Crystallization in the systems La-2(CO3)(3)center dot 6H(2)O-CaCO3(BaCO3)-R-H2O (R = Na2CO3, K2CO3, NaHCO3, KHCO3, NaCl, NH4Cl, CO(NH2)(2)) was studied under hydrothermal conditions (400-450 degrees C). The solid reaction products were found to contain LaOHCO3 and NaLa(CO3)(2). Detailed thermal decomposition schemes were proposed for these phases, and their lattice parameters were refined.