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 Number | 1308-38-9 <1> |
| PubChem CID | 517277 <1> |
| ChemSpider ID | 451305 <5> |
| UN Number | 3077 <1> |
| EC Number | 215-160-9 <1> |
| RTECS Number | GB6475000 <1> |
| InChI Key | QDOXWKRWXJOMAK-UHFFFAOYSA-N <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 Weight | 151.989 g/mol <1, 3> |
Physical Properties | |
| Color and Appearance | Dry, irradiate or dark green, well crystalline flour <1, 3> |
| Melting Point | 2,435 °C, 4,415 °F <1> |
| Boiling Point | 4,000 °C, 7,230 °F <1> |
| Density | 5.22 g cm-3 <1, 3> |
| State of issue at room temperature | Solid <1, 3> |
| Solubility | Insoluble in acetone and also alcohol, an extremely slightly dissolve in alkalies and also acids <1> |
| Solubility in Water | Practically 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 Structure | Hexagonal |
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Chromium (III) Oxide
Uses
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>.