Synthesis of Scheelite Group Minerals in the CaWO₄-CaMoO₄- PbMoO₄-PbWO₄ System from Aqueous Solutions at 100 °C

Abstract

Scheelite group minerals in the CaWO₄-CaMoO₄-PbMoO₄-PbWO₄ system have been synthesized at 100 °C by mixing of Na₂WO₄, Na₂MoO₄, CaCl₂, and PbCl₂ aqueous solutions. Powder X-ray diffraction data show that complete solid solutions exist in the CaWO₄-CaMoO₄ and PbWO₄-PbMoO₄ systems. On the other hand, solid solution are restricted near the end members in the CaWO₄-PbWO₄ and CaMoO₄-PbMoO₄ systems. All compounds belonging to the CaWO₄-CaMoO₄ system show fluorescent colors from cyan to yellow. In contrast, only compounds containing PbMoO₄ mole% from 0.5 to 1 show dark fluorescent color of pale green in the PbWO₄-PbMoO₄ system.