Gallium(III) sulfate
Chemical compound
From Wikipedia, the free encyclopedia
Gallium(III) sulfate refers to the chemical compound, a salt, with the formula Ga2(SO4)3, or its hydrates Ga2(SO4)3·xH2O. Gallium metal dissolves in sulfuric acid to form solutions containing [Ga(OH2)6]3+ and SO2−4 ions. The octadecahydrate Ga2(SO4)3·18H2O crystallises from these solutions at room temperature. This hydrate loses water in stages when heated, forming the anhydrate Ga2(SO4)3 above 150 °C[3] and completely above 310 °C.[1] Anhydrous Ga2(SO4)3 is isostructural with iron(III) sulfate, crystallizing in the rhombohedral space group R3.[4]
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3D model (JSmol) |
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| Properties | |
| Ga2(SO4)3 | |
| Molar mass | 445.7 g/mol |
| Appearance | White solid[1] |
| Density | 3.86 g/cm3[2] |
| Melting point | 680 °C (1,256 °F; 953 K)[1] (decomposes) |
| Slightly soluble[2] | |
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| H315, H319, H335 | |
| P302+P352, P305+P351+P338 | |
| NFPA 704 (fire diamond) | |
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Other cations |
Aluminium sulfate, Indium(III) sulfate, |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation
Gallium(III) sulfate is prepared from the reaction of hydroxygallium diacetate and sulfuric acid. The two reactants were mixed at 90 °C and left for 2 days which produced the octadecahydrate. Then, it was dried in a vacuum for two hours which created the extremely hygroscopic anhydrous form. The overall reaction is below:
- 2 Ga(CH3COO)2OH + 3 H2SO4 → Ga2(SO4)3 + 4 CH3COOH + 2 H2O
After the production, it was confirmed to be the simple salt, Ga2(SO4)3, by x-ray diffraction.[1]
Properties
When heated over 680 °C, gallium sulfate gives off sulfur trioxide, yielding gallium(III) oxide.[1] A gallium sulfate solution in water mixed with zinc sulfate can precipitate ZnGa2O4.[5]
Derivatives
Basic gallium sulfate is known with the formula (H3O)Ga3(SO4)2(OH)6.[6]
Double gallium sulfates are known with composition NaGa3(SO4)2(OH)6, KGa3(SO4)2(OH)6, RbGa3(SO4)2(OH)6, NH4Ga3(SO4)2(OH)6. These compounds are isostructural with jarosite and alunite. Jarosite and alunite can contain a small amount of gallium substituted for iron or aluminium.[6] Organic base double gallium sulfates can contain different core structures, these can be chains of [Ga(SO4)3]3-, [Ga(OH)(SO4)2]2- or [Ga(H2O)2(SO4)2]− or sheets of [Ga(H2O)2(SO4)2]− units.[7]
| formula | mw | crystal system |
space group |
unit cell Å | volume | density | properties | reference | |
|---|---|---|---|---|---|---|---|---|---|
| (H3O)Ga3(SO4)2(OH)6 | R3m | a = 7.18 c = 17.17 z = 1.5 |
766 | [8] | |||||
| Ga4(OH)10SO4 | [9] | ||||||||
| NH4Ga3(SO4)2(OH)6 | [7] | ||||||||
| trisodium gallium sulfate | Na3Ga(SO4)3 | tetragonal | a = 9.451 c = 7.097 |
[10] | |||||
| NaGa3(SO4)2(OH)6 | [7] | ||||||||
| KGa3(SO4)2(OH)6 | [7] | ||||||||
| RbGa3(SO4)2(OH)6 | [7] | ||||||||
| Caesium gallium sulfate dodecahydrate | CsGa(SO4)212H2O | cubic | Pa3 | Z=4 | 2.127 | refractive index=1.461 | [11] | ||
| dimethylammonium gallium sulfate hexahydrate | (CH3)2NH2Ga(SO4)2·6H2O | ferroeelastic | [12][13] | ||||||
| guanidinium gallium sulfate | [C(NH2)3]Ga(SO4)2·6H2O | hexagonal | P31m | a=11.82 c=9.13 | ferroelectric | [14] | |||
| Ethylenediammonium acid gallium sulfate | [C2H10N2][H3O][Ga(SO4)3] | [7] | |||||||
| Ethylenediammonium basic gallium sulfate | [C2H10N2][Ga(OH)(SO4)2]·H2O | [7] | |||||||
| Tetramethylenediammonium gallium sulfate | [C4H14N2][Ga(H2O)2(SO4)2]2 | [7] | |||||||
| Hexamethylenediammonium gallium sulfate | [C6H18N2][Ga(H2O)2(SO4)2]2 | [7] | |||||||
