Abstract
Stibnite, getchellite, wakabayashilite, and orpiment were synthesized by hydrothermal treatment of (Sb1−X, AsX)2S3 glass (0<x<1) with solvent of Na2S aqueous solution at 250–400°C, and 1000 kg/cm2 pressure to determine their formation conditions and solid solution ranges. The As–Sb substitution occurred up to x=0.24 in the above formula for stibnite, 0.54–0.64 for getchellite, 0.84–0.86 for wakabayashilite, and up to 0.83 for orpiment, respectively. Substitution of As for Sb in stibnite caused the elongation of the a axis and shortening of the b and c axes of the unit cell, and finally the a and b lengths became equal at about 25 mol% As. Wakabayashilite, synthesized for the first time in the present experiment, does not have the superstructure known for natural materials and its powder diffraction data are presented.
