Thermal properties and thermochemistry of lanthanide chromates

摘要

The behavior of chromates Ln_2(CrO_4)_3 centre dot 7H2O and Rb_5Ln(CrO_4)_2(Ln=La,Pr,Nd,Sm,and Gd)was studied by derivatography as they were heated in air in a temperature interval of 300-1470 K.The high-temperature enthalpies of LaCrO_3 and YCrO_3 at 865-1350 K and enthalpies of solution of La_2(CrO_4)_3 centre dot 7H_2O in a solution of nitric acid at 298 K were measured by calorimetric methods.The standard enthalpies of formation were calculated for some compounds of composition Ln_2(CrO_4)_3 centre dot 2H_2O and LnCrO_3.