Phase transition and lattice parameter variation with temperature of potassium lithium sulphate have been studied. Precision lattice parameters have been determined at various temperatures, ranging 30°C to 400°C. The diffraction pattern obtained above 435°C differs from that taken at room temperature suggesting a structural change, contrary to the reports of Fischmeister and others.

Pressure induced phase transition in mercurous chloride has been studied by high pressure x-ray diamond anvil cell. The change in diffraction pattern started and ended at a pressure of about 5 kbar and 20 kbar respectively. The patterns recorded at 20 kbar could be indexed basing on an orthorhombic lattice, with lattice parametersa=4.23 Å,b=4.54 Å andc=10.44 Å.