Lanthanum(III) iodide
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| Names | |
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| Other names
Lanthanum triiodide | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.034.045 |
| EC Number |
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PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| LaI 3 | |
| Molar mass | 519.62 |
| Density | 5.63 g/mL at 25 °C |
| Melting point | 772 °C (1,422 °F; 1,045 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Lanthanum(III) iodide is an inorganic compound containing lanthanum and iodine with the chemical formula LaI
3.[1]
Lanthanum(III) iodide can be synthesised by the reaction of lanthanum metal with mercury(II) iodide:[2][3]
- 2 La + 3 HgI2 → 2 LaI3 + 3 Hg
It can also be prepared from the elements, that is by the reaction of metallic lanthanum with iodine:[2]
- 2 La + 3 I2 → 2 LaI3
While lanthanum(III) iodide solutions can be generated by dissolving lanthanum oxide in hydroiodic acid, the product will hydrolyse and form polymeric hydroxy species:[4]
- La2O3 + 6 HI → 2 LaI3 + 3 H2O → further reactions
Structure
Lanthanum(III) iodide adopts the same crystal structure as plutonium(III) bromide, with 8-coordinate metal centres arranged in layers.[4][5] This orthorhombic structure is typical of the triiodides of the lighter lanthanides (La–Nd), whereas heavier lanthanides tend to adopt the hexagonal bismuth(III) iodide structure.[3]