Potassium dichromate
Potassium dichromate, K2Cr2O7, is a common inorganic chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications. As with all hexavalent chromium compounds, it is acutely and chronically harmful to health. It is a crystalline ionic solid with a very bright, red-orange color. The salt is popular in laboratories because it is not deliquescent, in contrast to the more industrially relevant salt sodium dichromate.
| Names | |
|---|---|
| IUPAC name
Potassium dichromate(VI) | |
| Other names
potassium bichromate bichromate of potash | |
| Identifiers | |
3D model (JSmol) |
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| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.029.005 |
| EC Number |
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PubChem CID |
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| RTECS number |
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| UNII | |
| UN number | 3288 |
CompTox Dashboard (EPA) |
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| Properties | |
| K2Cr2O7 | |
| Molar mass | 294.185 g/mol |
| Appearance | red-orange crystalline solid |
| Odor | odorless |
| Density | 2.676 g/cm3, solid |
| Melting point | 398 °C (748 °F; 671 K) |
| Boiling point | 500 °C (932 °F; 773 K) decomposes |
| 4.9 g/100 mL (0 °C) 13 g/100 mL (20 °C) 102 g/100 mL (100 °C) | |
| Solubility | insoluble in alcohol, acetone. |
Refractive index (nD) |
1.738 |
| Structure | |
| Triclinic (α-form, <241.6 °C) | |
| Tetrahedral (for Cr) | |
| Thermochemistry | |
Heat capacity (C) |
219 J/mol |
Std molar entropy (S⦵298) |
291.2 J/(K·mol) |
Std enthalpy of formation (ΔfH⦵298) |
−2033 kJ/mol |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards |
carcinogenic, corrosive |
| GHS labelling: | |
| NFPA 704 (fire diamond) | |
| Flash point | Non-flammable |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) |
25 mg/kg (oral, rat) |
| Safety data sheet (SDS) | ICSC 1371 |
| Related compounds | |
Other anions |
Potassium chromate Potassium molybdate Potassium tungstate |
Other cations |
Ammonium dichromate Sodium dichromate |
Related compounds |
Potassium permanganate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references | |
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