抄録
Crystals of ferrian braunite were synthesized using evacuated silica glass tube at 1000°C, and the chemical composition and the cell dimensions of the run products were determined. Under this condition, ferric ions replaced trivalent manganese ions of braunite up to 40%. The cell dimension, especially the length of the c-axis, increases in proportion to Fe3+⁄(Fe3++Mn3+) of braunite, in spite of the nearly equal radius of ferric ion to that of trivalent manganese ion. This substitution is thought to bring about the releasing of distortion of trivalent manganese ions by Jahn-Teller effect and to result in the increase of cell dimension.
