Difference between revisions of "Chromium(III) chloride"
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Chromium chloride hexahydrate can be obtained by reacting chromium oxide, hydroxide or plain chromium metal with conc. hydrochloric acid. | Chromium chloride hexahydrate can be obtained by reacting chromium oxide, hydroxide or plain chromium metal with conc. hydrochloric acid. | ||
| − | Chromium chloride anhydrous can be prepared by reacting | + | Chromium chloride anhydrous can be prepared by reacting chromium hydroxide, [[chromium(III) oxide]] or just chromium metal with [[hydrochloric acid]] in [[methanol]]. Alternatively, hexahydrate chromium chloride is treated with [[thionyl chloride]], yielding very dry CrCl<sub>3</sub>. |
A more energetic route involves the carbothermic chlorination of chromium(III) oxide between 650–800 °C. | A more energetic route involves the carbothermic chlorination of chromium(III) oxide between 650–800 °C. | ||
Latest revision as of 21:34, 7 May 2020
| Names | |
|---|---|
| IUPAC name
Chromium(III) chloride
| |
| Other names
Chromic chloride
Chromium trichloride | |
| Properties | |
| CrCl3 | |
| Molar mass | 158.36 g/mol (anhydrous) 266.45 g/mol (hexahydrate) |
| Appearance | Purple (anhydrous) Dark green (hexahydrate) |
| Odor | Odorless |
| Density | 2.87 g/cm3 (anhydrous) 1.76 g/cm3 (hexahydrate) |
| Melting point | 1,152 °C (2,106 °F; 1,425 K) (anhydrous) 83 °C (181 °F; 356 K) (hexahydrate) |
| Boiling point | 1,300 °C (2,370 °F; 1,570 K) (decomposes) |
| anhydrous Almost insoluble hexahydrate 58.5 g/100 ml (20 °C) | |
| Solubility | Insoluble in acetone, diethyl ether, ethanol |
| Hazards | |
| Safety data sheet | Sigma-Aldrich (anhydrous) Sigma-Aldrich (hexahydrate) |
| Flash point | Non-flammable |
| Lethal dose or concentration (LD, LC): | |
| LD50 (Median dose)
|
1,870 mg/kg (rat, oral) |
| Related compounds | |
| Related compounds
|
Iron(III) chloride |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Chromium(III) chloride (CrCl3) is a compound of chromium. It is available in two forms, anhydrous and hydrated.
Contents
Properties
Chemical
Chromium(III) chloride will react with bases to give chromium hydroxide.
Physical
Chromium(III) chloride is a purple (anhydrous) or dark green (hydrated) solid.
Availability
Chromium chloride is sold by chemical suppliers.
Preparation
Chromium chloride hexahydrate can be obtained by reacting chromium oxide, hydroxide or plain chromium metal with conc. hydrochloric acid.
Chromium chloride anhydrous can be prepared by reacting chromium hydroxide, chromium(III) oxide or just chromium metal with hydrochloric acid in methanol. Alternatively, hexahydrate chromium chloride is treated with thionyl chloride, yielding very dry CrCl3.
A more energetic route involves the carbothermic chlorination of chromium(III) oxide between 650–800 °C.
Reacting chlorine gas with hot chromium metal will also give anhydrous CrCl3.
Heating chromium(III) chloride hexahydrate in air will cause some of it to oxidize, resulting in CrCl3 contaminated with chromium oxide and oxychloride. To obtain the anhydrous form from the hexahydrate, you must heat the CrCl3 in the presence of a chlorine or chloride source, like thionyl chloride or dry hydrogen chloride gas.
Projects
- Make chromates and dichromates
- Make chromium(II) chloride
- Make Cr coordination complexes and adducts
- Make organochromium compounds
Handling
Safety
While less toxic than Cr(VI) compounds, chromium chloride is less toxic, although it's still quite harmful.
Storage
In closed bottles, air-tight for the anhydrous form.
Disposal
Should be converted to less soluble forms and sent to disposal facilities. You can also recycle it.
