Synthesis of gerstleyite

Abstract

Gerstleyite [Na₂Sb₈S₁₃·2H₂O] was successfully synthesized by hydrothermal method for the first time. The syntheses condition was as follows: starting material Sb₂S₃ and Na₂S·9H₂O soln. with mixing ratio of [Sb/Na]=4.0 and 8.0 (mol/mol), heating temperature 210 and 220°C, and heating time of 80 hours. The products were identified to be gerstleyite by means of X-ray powder diffraction. Space group and lattice constants were examined by a Weissenberg camera. Crystal data: monoclinic, Cm, a=9.945(2), b=23.134(3), c=7.108(1) Å, β=127.828(8)°. The lattice parameters of the synthetic gerstleyite are 0.2∼0.4% larger than those reported for natural gerstleyite [Na₂(Sb, As)₈S₁₃·2H₂O], in which about one tenth of the Sb atoms were substituted by smaller As atoms.