Europium(III) iodide is an inorganic compound containing europium and iodine with the chemical formula EuI3.[1]
Names | |
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IUPAC name Europium(III) iodide | |
Other names Europium triiodide | |
Identifiers | |
3D model (JSmol) | |
ChemSpider | |
ECHA InfoCard | 100.033.941 |
EC Number |
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PubChem CID | |
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Properties | |
EuI 3 | |
Molar mass | 532.677 g mol−1 |
Appearance | colourless crystals[2] |
Melting point | decomposes[1] |
Structure[1][3][4] | |
BiI3 | |
octahedral | |
Related compounds | |
Other anions | EuF3, EuCl3, EuBr3 |
Other cations | SmI3, GdI3 |
Related compounds | EuI2 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Preparation
Europium metal reacts directly with iodine to form europium(III) iodide:[5]
- 2 Eu + 3 I2 → 2 EuI3
Hydrated europium(III) iodide can be prepared dissolving europium(III) oxide or europium(III) carbonate in hydroiodic acid:[1][6]
- Eu2O3 + 6 HI + 6 H2O → 2 EuI3·9H2O
Europium powder reacts with iodine in THF to form a THF adduct of europium(III) iodide:[7][8]
- 2 Eu + 3 I2 + 7 THF → [EuI2(THF)5][EuI4(THF)2]
The adduct can be formulated more simply as EuI3(THF)3.5.
Structure
Europium(III) iodide adopts the bismuth(III) iodide (BiI3) crystal structure type,[3][4] with octahedral coordination of each Eu3+ ion by 6 iodide ions.[1]
Reactivity
Europium(III) iodide is used as the starting material for two of the main ways of preparing europium(II) iodide:[9]
Reduction with hydrogen gas at 350 °C:
- 2 EuI3 + H2 → 2 EuI2 + 2 HI
Thermal decomposition[1] at 200 °C, a disproportionation reaction:
- 2 EuI3 → 2 EuI2 + 2 I2
Europium(III) iodide nonahydrate, EuI3·9H2O, thermally decomposes to europium(II) iodide dihydrate, EuI2·H2O.[10]