Mineralogical Journal · 1964 · 32 citations · 0 references
Natural SciencesChemistryMaterials ScienceCrystal StructurePhysical ChemistrySolid State PhysicsCrystal SystemsCrystallographyPhase TransitionsX-ray CrystallographyX-ray Data AnalysisX-ray DiffractionHigh-temperature Phase RelationsPowder Diffraction AnalysisPowder X-ray DiffractionRoom-temperature CrystallographyUnit Cell DeterminationUnit Cell GeometryX-ray ChemistryX-ray Diffraction Phase Analysis
Four phases named S1, S2, S3 and S4 in tridymite of type S were confirmed on the close examination of the change of X-ray powder reflections with increasing temperatures.Unit cell dimensions are: S1; monoclinic, a=10.04Å, b=17.28Å, c=8.20Å, β=91.50°, S2; orthorhombic, a=10.04Å, b=17.28Å, c=8.20Å, S3; domain structure, and S4; hexagonal, a=5.046-5.06Å, c=8.236-8.30Å. Their relations are as follows, S1 → 60-75°C S2 → 115° S3 → 250°C S4. Though the change of the patterns with decreasing temperatures is not thoroughly investigated, the transition is reversible.