Chromium (iii) oxide, generally called chromia and referred to together oxo(oxochromiooxy)chromium in IUPAC nomenclature, is an inorganic compound containing chromium and oxygen stood for by the chemical formula Cr2O3 <1>. It normally occurs together the mineral eskolaite and is a very insoluble compound with high heat stability, having actually the nature of both an acid and also a basic <2, 3, 4>.

Chromium (III) Oxide Identification

CAS Number1308-38-9 <1>
PubChem CID517277 <1>
ChemSpider ID451305 <5>
UN Number3077 <1>
EC Number215-160-9 <1>
RTECS NumberGB6475000 <1>

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Chromium (III) Oxide Formula

How is Chromium (III) Oxide Prepared

It is produced through the reduction of salt dichromate using sulfur in ~ high temperatures suggested by the oxidization reaction <6>:

Na2Cr2O7 + S → Na2SO4 + Cr2O3

Ammonium dichromate, on heating, decomposes right into chromium (iii) oxide, water, and also nitrogen <7>:

(NH4)2Cr2O7 → Cr2O3 + N2 + 4H2O

Chromium (iii) carbonate is boil to type chromium (iii) oxide and carbon dioxide:

Cr2(CO3)3 → Cr2O3 + 3CO2

Reaction with other Compounds

Chromium (III) Oxide v Hydrochloric Acid

It reacts with dilute hydrochloric mountain to form chromium (iii) chloride and water <8>:

Cr2O3 + 6HCl → 2CrCl3 + 3H2O

Chromium (III) Oxide with Hydrogen Sulfide

When chromium (iii) oxide reacts v gaseous hydrogen sulfide, it returns chromium (iii) sulfide and water:

Cr2O3 + 3H2S → Cr2S3 + 3H2O

Properties and also Characteristics of Chromium (III) Oxide

General Properties

Molar Mass/Molecular Weight151.989 g/mol <1, 3>

Physical Properties

Color and AppearanceDry, irradiate or dark green, well crystalline flour <1, 3>
Melting Point2,435 °C, 4,415 °F <1>
Boiling Point4,000 °C, 7,230 °F <1>
Density5.22 g cm-3 <1, 3>
State of issue at room temperatureSolid <1, 3>
SolubilityInsoluble in acetone and also alcohol, an extremely slightly dissolve in alkalies and also acids <1>
Solubility in WaterPractically insoluble, 2.96 µg/L (20 °C, pH 8), 3.13 µg/L (20 °C, pH 6) <1>
Magnetic Susceptibility (χ) 1960.0 X 10-6 cm3/mol

Atomic Properties

Crystal StructureHexagonal

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Chromium (III) Oxide


Because that its stability, chromium (iii) oxide is used as the eco-friendly pigment in inks, glasses, and also paints and as a colorant because that ceramics, and also producing a faint green tinge in glazes <8>.It serves together an abrasive for sprucing up or stropping the edges of razors, knives, and surfaces of optical devices <9>.

Is the Safe

Exposure to chromium (iii) oxide with mouth and also skin can cause acute toxicity <1>. That may cause an allergy skin reaction and also serious eye damage <1>. That can likewise cause reproductive toxicity and is harmful to the unborn kid <1>.