Ijzersulfur

Ijzersulfur, or iron sulfide, refers to a group of binary compounds composed of iron and sulfur. The most common forms are iron(II) sulfide (FeS), iron disulfide (FeS2, known as pyrite in English), and non-stoichiometric iron sulfides such as Fe1−xS (pyrrhotite). Troilite (FeS) is a mineral form of iron sulfide that is more common in meteorites than on Earth.

Occurrence and minerals: Pyrite (FeS2) is one of the most widespread sulfide minerals, found in a variety of rocks including igneous, sedimentary, and metamorphic types. Troilite (FeS) occurs in meteorites and some iron-rich planetary materials. Pyrrhotite (Fe1−xS) is common in ultramafic and mafic rocks and in certain ore deposits. In hydrothermal and sedimentary environments, iron sulfides can form through reactions between iron-bearing minerals and sulfur-bearing fluids under reducing conditions.

Properties: Iron sulfides generally have low solubility in water and can be chemically reactive, especially when exposed to air or acidic conditions. Pyrite is typically metallic-bronze in luster and pale to black in streak, while troilite appears more metallic and dark. Pyrrhotite often shows magnetic properties that vary with composition. Oxidation of iron sulfides in the environment can produce sulfuric acid and hydrogen sulfide, linked to environmental concerns such as acid mine drainage.

Uses and significance: Iron sulfides occur as valuable ore minerals in some deposits and serve as precursors in the synthesis of iron sulfide materials used in catalysis and battery research. They also play a notable role in geological and planetary sciences as indicators of redox conditions and ore-forming processes.