sulfidic

Sulfidic refers to materials, environments, or processes that contain or are associated with sulfide compounds, typically composed of sulfur and a metal such as iron, copper, and zinc. The term is most commonly used in geology, mining, and environmental science to describe ore deposits, mine tailings, and natural waters that exhibit significant sulfide content. Within a rock formation, a sulfidic zone may indicate past hydrothermal activity or the presence of ore minerals like pyrite (FeS₂), chalcopyrite (CuFeS₂), and sphalerite (ZnS).

Sulfidic conditions arise when sulfur is available and reduced to its elemental form (S²⁻) through biological or abiotic processes. In sedimentary basins, sulfate-reducing bacteria convert sulfate to sulfide, further reacting with dissolved metals to form metal sulfides. Geological sulfidic layers often host economically significant ore bodies; worldwide, copper, lead, and zinc deposits frequently occur in or adjacent to sulfur-rich strata. The oxidation of sulfide minerals at the Earth's surface generates sulfuric acid, a process that can contribute to acid mine drainage. This environmental challenge can mobilize heavy metals into surrounding soil and waterways, necessitating careful remediation strategies.

In chemistry, sulfidic species are precursors to many industrially relevant compounds, such as metal sulfide catalysts used in hydrogenation reactions. The term may also denote a hydrothermal fluid enriched in hydrogen sulfide, which can promote deep-sea vent ecosystems rich in chemosynthetic organisms. In environmental monitoring, sulfidic water is identified by its characteristic foul odor, metallic taste, and color resulting from dissolved metal sulfides.