Abstract
Changes on the lattice constants of fluorine bearing phlogopite occurring on heating were studied by X-ray diffraction method, and were discussed from the structural point of view.
The phlogopite shows a prominent loss in weight between 1000°C and 1200°C, and a contraction of the lattice is observed for the phlogopite heated at temperatures higher than 900°C. The contraction of the lattice for the phlogopite heated in air is larger than that for the phlogopite heated in argon. Structural parameters of Suzorite mica and those of Suzorite mica heated at 1000°C are predicted from their chemical compositions and lattice constants. As is obvious from the predicted structural parameters mentioned above, the flattening of the octahedral sheet is occurred by the oxidation of the transition elements in the octahedra on heating. The contraction of the lattice, therefore, might be attributable to the oxidation of the transition elements in the octahedra.
