Gallium trichloride
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| Names | |
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| Other names
Gallium(III) chloride, Trichlorogallium, Trichlorogallane
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| Identifiers | |
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3D model (Jmol)
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| ChemSpider | |
| ECHA InfoCard | 100.033.268 |
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PubChem CID
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| RTECS number | LW9100000 |
| UNII | |
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| Properties | |
| Cl3Ga | |
| Molar mass | 176.07 g·mol−1 |
| Appearance | colorless crystals deliquescent |
| Density | 2.47 g/cm3 2.053 g/cm3 at melting point |
| Melting point | 77.9 °C (172.2 °F; 351.0 K) (anhydrous) 44.4 °C (hydrate) |
| Boiling point | 201 °C (394 °F; 474 K) |
| very soluble | |
| Solubility | soluble in benzene, CCl4, CS2 |
| −63.0·10−6 cm3/mol | |
| Hazards | |
| NFPA 704 | |
| Flash point | Non-flammable |
| Lethal dose or concentration (LD, LC): | |
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LD50 (median dose)
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4700 mg/kg (rat, oral) |
| Related compounds | |
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Other anions
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Gallium(III) fluoride Gallium(III) bromide Gallium(III) iodide |
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Other cations
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Aluminium chloride Indium(III) chloride Thallium(III) chloride |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 (what is   ?) |
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| Infobox references | |
Gallium trichloride is the chemical compound with the formula GaCl3. Solid gallium trichloride exists as a dimer with the formula Ga2Cl6. It is colourless and soluble in virtually all solvents, even alkanes, which is truly unusual for a metal halide. It is the main precursor to most derivatives of gallium and a reagent in organic synthesis.
As a Lewis acid, GaCl3 is milder than aluminium trichloride. Gallium(III) is easier to reduce than Al(III), so the chemistry of reduced gallium compounds is more extensive than for aluminium. Ga2Cl4 is known whereas the corresponding Al2Cl4 is not. The coordination chemistry of Ga(III) and Fe(III) are similar, and gallium(III) compounds have been used as diamagnetic analogues of ferric compounds.
Gallium trichloride can be prepared from the elements, heating gallium metal in a stream of chlorine, and purifying the product by sublimation under vacuum.
It can also be prepared from by heating gallium oxide with thionyl chloride:
Gallium metal reacts slowly with hydrochloric acid. This reaction produces hydrogen gas slowly.
As a solid, it adopts a bitetrahedral structure with two bridging chlorides. Its structure resembles that of aluminium tribromide. In contrast AlCl3 and InCl3 feature contain 6 coordinate metal centers. As a consequence of its molecular nature and associated low lattice energy, gallium trichloride has a lower melting point vs the aluminium and indium trihalides. The formula of Ga2Cl6 is often written as Ga2(μ-Cl)2Cl4. In the gas phase the dimers dissociate to trigonal planar monomers.
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