Acta Crystallographica Section B

Structural Science

Volume 56, Part 4 (August 2000)

research papers

Acta Cryst. (2000). B56, 607-617 [ doi:10.1107/S0108768100003219 ]

Analysis of LiKSO₄ crystals in the temperature range from 573 to 943 K

C. B. Pinheiro, M. A. Pimenta, G. Chapuis and N. L. Speziali

Abstract: The structural phases observed in LiKSO crystals due to thermotropic transitions have been studied for more than a century. Nowadays many different phases are referenced, but some of the results are still controversial. Structural studies by single-crystal X-ray diffraction from room temperature to 803 K are presented here. Phase II (708 $\lt$ T $\lt$ 943 K) is extensively discussed on the basis of ordered and disordered models, using harmonic and anharmonic atomic displacements, and considering a twinned crystal composed of three orthorhombic domains. Analyses of the same phase at different temperatures determine the best structure model.

Keywords: Lithium potassium sulfate; Thermotropic phase transitions.