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| Names | |
|---|---|
| Other names Iron sulfide, ferrous sulfide, black iron sulfide, protosulphuret of iron | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider |
|
| ECHA InfoCard | 100.013.881 |
| UNII | |
| |
| |
| Properties | |
| FeS | |
| Molar mass | 87.910 g/mol |
| Appearance | Grey, sometimes in lumps or powder |
| Density | 4.84 g/cm3 |
| Melting point | 1,194 °C (2,181 °F; 1,467 K) |
| negligible (insoluble) | |
| Solubility | reacts inacid |
| +1074·10−6 cm3/mol | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards | Source ofhydrogen sulfide, can be pyrophoric |
| NFPA 704 (fire diamond) | |
| variable | |
| Related compounds | |
Otheranions | Iron(II) oxide Iron(II) selenide Iron(II) telluride |
Othercations | Manganese(II) sulfide Cobalt(II) sulfide |
| Iron(III) sulfide | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Iron(II) sulfide orferrous sulfide (Br.E.sulphide) is one of a family ofchemical compounds andminerals with the approximateformulaFeS. Iron sulfides are often iron-deficientnon-stoichiometric. All are black, water-insoluble solids.
FeS can be obtained by the heating of iron andsulfur:[1]
FeS adopts thenickel arsenide structure, featuringoctahedral Fe centers and trigonal prismatic sulfide sites.
Iron sulfide reacts withhydrochloric acid, releasinghydrogen sulfide:[2]
In moist air, iron sulfides oxidize to hydratedferrous sulfate.
Iron sulfides occur widely in nature in the form ofiron–sulfur proteins.
As organic matter decays under low-oxygen (orhypoxic) conditions such as in swamps ordead zones of lakes and oceans,sulfate-reducing bacteria reduce varioussulfates present in the water, producinghydrogen sulfide. Some of the hydrogen sulfide will react with metal ions in the water or solid to produce iron or metal sulfides, which are not water-soluble. These metal sulfides, such as iron(II) sulfide, are often black or brown, leading to the color of sludge.
Pyrrhotite is a waste product of theDesulfovibrio bacteria, a sulfate reducing bacteria.
When eggs are cooked for a long time, theyolk's surface may turn green. This color change is due to iron(II) sulfide, which forms as iron from the yolk reacts with hydrogen sulfide released from the egg white by the heat.[3][4] This reaction occurs more rapidly in older eggs as the whites are more alkaline.[5]
The presence of ferrous sulfide as a visible blackprecipitate in thegrowth mediumpeptone iron agar can be used to distinguish betweenmicroorganisms that produce thecysteine metabolizing enzymecysteine desulfhydrase and those that do not. Peptone iron agar contains theamino acidcysteine and achemical indicator,ferric citrate. The degradation of cysteine releaseshydrogen sulfide gas that reacts with theferriccitrate to produce ferrous sulfide.
