Used in the production of bismuth metal and its alloys, particularly in low-melting-point alloys for fire detection and suppression systems. Employed as a pigment in cosmetics and artist materials due to its dark color and luster. Applied in some specialized thermoelectric materials because of its semiconductor properties. Investigated for use in environmental remediation to remove heavy metals and sulfur compounds from wastewater. Also found in certain high-temperature soldering applications and in the synthesis of nanomaterials for electronic and optical devices.