Syntheses of complex sulfides AgCuS and Ag_3CuS_2 from the elements under hydrothermal conditions(<Feature>Aqueous Solution Science for Ceramic Processing II)

The hydrothermal technique was applied to the syntheses of ternary metal sulfides, AgCuS and Ag_3CuS_2, using silver, copper, and sulfur powders as starting materials. AgCuS was obtained as a single phase when the starting ratio of Ag:Cu:S was 0.9:1.1:1 in water above 120℃ for 10h except for synthesis condition at 120℃ for 60h and inductively coupled plasma (ICP) analysis revealed that experimental silver and copper contents in products were Ag_<0.89>Cu_<1.10>S. At 120℃ for 60h, some unidentified peaks were observed in the powder X-ray diffraction (XRD) pattern and plate crystals of new compound were found in addition to AgCuS particles from the field emission scanning electron microscopy (FE-SEM) image. Pure Ag_3CuS_2 was also prepared by a simple reaction of stoichiometric silver, copper, and sulfur powders above 90℃, and the composition of products was Ag_<2.99>Cu_<1.00>S.