Beryllium iodide
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| Names | |
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| Systematic IUPAC name
Beryllium iodide | |
| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.029.199 |
PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| BeI2 | |
| Molar mass | 262.82112 g·mol−1 |
| Appearance | colorless needle-like crystals |
| Density | 4.325 g/cm3 |
| Melting point | 480 °C (896 °F; 753 K) |
| Boiling point | 590 °C (1,094 °F; 863 K)[1] |
| reacts with water[1][citation needed] | |
| Solubility | Slightly soluble in CS2 Soluble in ethanol, diethyl ether[2] |
| Structure | |
| orthorhombic | |
| Thermochemistry | |
Heat capacity (C)
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71.14 J/(mol·K) |
Std molar
entropy (S⦵298) |
130 J/(mol·K) |
Std enthalpy of
formation (ΔfH⦵298) |
−192.62 kJ/mol |
Gibbs free energy (ΔfG⦵)
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−210 kJ/mol |
Std enthalpy of
combustion (ΔcH⦵298) |
19 kJ/mol |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
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see Berylliosis |
| NFPA 704 (fire diamond) | |
| NIOSH (US health exposure limits): | |
PEL (Permissible)
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TWA 0.002 mg/m3 C 0.005 mg/m3 (30 minutes), with a maximum peak of 0.025 mg/m3 (as Be)[3] |
REL (Recommended)
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Ca C 0.0005 mg/m3 (as Be)[3] |
IDLH (Immediate danger)
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Ca [4 mg/m3 (as Be)][3] |
| Related compounds | |
Other anions
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Other cations
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Related compounds
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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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Beryllium iodide is an inorganic compound with the chemical formula BeI2. It is a hygroscopic white solid. The Be2+ cation, which is relevant to salt-like BeI2, is characterized by the highest known charge density (Z/r = 6.45), making it one of the hardest cations and a very strong Lewis acid.[4]
Reactions
[edit]Beryllium iodide can be prepared by reacting beryllium metal with elemental iodine at temperatures of 500 °C to 700 °C:[1]
- Be + I2 → BeI2
When the oxidation is conducted on an ether suspension of elemental Be, one obtains colorless dietherate:[5]
- Be + I2 + 2 O(C2H5)2 → BeI2(O(C2H5)2)2
The same dietherate is obtained by suspending beryllium iodide in diethyl ether:[5]
- BeI2 + 2 O(C2H5)2 → BeI2(O(C2H5)2)2
This ether ligands in BeI2(O(C2H5)2)2 can be displaced by other Lewis bases.
Beryllium iodide reacts with fluorine giving beryllium fluoride and fluorides of iodine, with chlorine giving beryllium chloride, and with bromine giving beryllium bromide.
Structure
[edit]Two forms (polymorphs) of BeI2 are known. Both structures consist tetrahedral Be2+ centers interconnected by doubly bridging iodide ligands. One form consist of edge-sharing polytetrahedra. The other form resembles zinc iodide with interconnected adamantane-like cages.[6]
Applications
[edit]Beryllium iodide can be used in the preparation of high-purity beryllium by the decomposition of the compound on a hot tungsten filament.
References
[edit]- ^ a b c Perry, Dale L.; Phillips, Sidney L. (1995), Handbook of Inorganic Compounds, CRC Press, p. 63, ISBN 0-8493-8671-3, retrieved 2007-12-10
- ^ Parsons, Charles Lathrop (1909), The Chemistry and Literature of Beryllium, Easton, Pa.: Chemical Publishing, pp. 22–23, retrieved 2007-12-10
- ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0054". National Institute for Occupational Safety and Health (NIOSH).
- ^ Buchner, M. R. (2017-01-01), "Beryllium Chemistry", Reference Module in Chemistry, Molecular Sciences and Chemical Engineering, Elsevier, ISBN 978-0-12-409547-2, retrieved 2022-10-27
- ^ a b Paparo, Albert; Jones, Cameron (2019-02-01). "Beryllium Halide Complexes Incorporating Neutral or Anionic Ligands: Potential Precursors for Beryllium Chemistry". Chemistry: An Asian Journal. 14 (3): 486–490. doi:10.1002/asia.201801800. ISSN 1861-4728. PMID 30604490. S2CID 58632466.
- ^ Troyanov, S.I. (2000). "Crystal Modifications of Beryllium Dihalides BeCl2, BeBr2 and BeI2". Zhurnal Neorganicheskoi Khimii. 45: 1619–1624.