| Identification | Back Directory | [Name]
Nickel sulfide crystalline particles | [CAS]
1314-04-1 | [Synonyms]
Millerite
Ccris 3733
Nickel sulfide (millerite)
Nickel sulfide crystalline particles
Nickel sulfide [nickel and nickel compounds] | [Molecular Formula]
NiS | [MOL File]
1314-04-1.mol | [Molecular Weight]
90.7584 |
| Questions And Answer | Back Directory | [Occurrence and Uses]
Nickel sulfide crystalline particles occurs in nature as mineral millerite. Its principal use is as a source material for making nickel metal.
| [Preparation]
Nickel sulfide crystalline particles is mined directly from natural deposits. Also, it can be prepared in the laboratory by precipitation from an aqueous solution of a nickel salt with ammonium sulfide, (NH4)2S, or by precipitation from an acetic acid solution with hydrogen sulfide. While the aqueous solution method yields an amorphous product (alpha-NiS) which rapidly changes on exposure to air and contact with the solution to a brown crystalline sulfide (beta-NiS), the acid solution method forms only crystalline beta-NiS.
Nickel sulfide crystalline particles also can be prepared by reacting nickel powder with molten sulfur.
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| Hazard Information | Back Directory | [Chemical Properties]
The mineral millerite is brittle; hardness, 3–3.5; specific gravity, 5.48–5.52; luster, metallic; color, brass-yellow, often with an iridescent tarnish. | [Physical properties]
Trigonal crystalline solid or amorphous powder; mineral millerite has a yellow metallic luster; color varies from yellow to brownish black; density 5.30 to 6.65 g/cm3; exhibits three allotropic modifications: (1) the acid-soluble amorphous alpha form obtained from nickel salt solution by precipitation with ammonium sulfide, (2) the alpha form rapidly transforms to a crystalline beta form as a brown colloidal dispersion upon exposure to air, and (3) a rhombohedral gamma modification found native as mineral millerite, which also can be prepared artificially under certain conditions.
Gamma-NiS slowly converts to beta-NiS in solution. Beta form probably is richer in sulfur than alpha and gamma modifications and therefore they could have varying stoichiometric compositions.
Nickel sulfide melts at 797°C and is insoluble in water (3.6 mg/L at 18°C; soluble in concentrated nitric acid and potassium hydrogen sulfide solution; slightly soluble in alcohol. | [Occurrence]
Nickel sulfide occurs in nature as mineral millerite. Its principal use is as a source material for making nickel metal. | [Uses]
MILLERITE is used as an ore of nickel. Millerite was named for the English mineralogist, W.H. Miller. |
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