KLa(SO4)2-SrSO4 System at Temperatures above 600°C

The KLa(SO4)(2)-SrSO4 system has been studied at temperatures above 600 degrees C by X-ray diffraction and thermogravimetric analysis. The results demonstrate that the system contains a broad range (0-70 mol % KLa(SO4)(2)) of solid solutions based on the orthorhombic phase beta-SrSO4 (sp. gr. Pnma). We have determined the unit-cell parameters of the solid solutions. Their unit-cell volume has been shown to increase systematically from 307.67(6) to 313.54(21) angstrom(3) in the composition range studied. The solid solutions result from heterovalent substitution of potassium and lanthanum ions for two strontium ions and decompose above a temperature of 950 degrees C to form the SO3 and La2O3 oxides and potassium and strontium sulfates.

Automated summary

The KLa(SO4)(2)-SrSO4 system was studied at temperatures above 600 degrees C by X-ray diffraction and thermogravimetric analysis. The results show the presence of solid solutions based on the orthorhombic phase beta-SrSO4, covering a broad range of compositions (0-70 mol % KLa(SO4)(2)). The unit-cell parameters and volume of the solid solutions were determined and found to increase systematically with composition. The formation of the solid solutions is due to heterovalent substitution of potassium and lanthanum ions for strontium ions, and they decompose above 950 degrees C to produce oxides and sulfates.