Beryllium oxide
Names | |
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Preferred IUPAC name
Beryllium(II) monoxide | |
Systematic IUPAC name
Oxoberyllium | |
Other names
Beryllia, Thermalox, Bromellite, Thermalox 995.[1]
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Identifiers | |
3D model (
JSmol ) |
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3902801 | |
ChEBI | |
ChemSpider | |
ECHA InfoCard
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100.013.758 |
EC Number |
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MeSH | beryllium+oxide |
PubChem CID
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RTECS number
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UNII | |
UN number | 1566 |
CompTox Dashboard (EPA)
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Properties | |
BeO | |
Molar mass | 25.011 g·mol−1 |
Appearance | Colourless, vitreous crystals |
Odor | Odourless |
Density | 3.01 g/cm3[2] |
Melting point | 2,578 °C (4,672 °F; 2,851 K)[2] |
Band gap | 10.6 eV[3] |
−11.9·10−6 cm3/mol[4] | |
Thermal conductivity
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210 W/(m·K)[5] |
Refractive index (nD)
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n11.7184, n2=1.733[6][7] |
Structure[8] | |
Hexagonal, zincite | |
P63mc | |
C6v | |
a = 2.6979 Å, c = 4.3772 Å
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Formula units (Z)
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2 |
Linear | |
Thermochemistry[9] | |
Heat capacity (C)
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25.6 J/(K·mol) |
Std molar
entropy (S⦵298) |
13.77±0.04 J/(K·mol) |
Std enthalpy of (ΔfH⦵298)formation |
−609.4±2.5 kJ/mol |
Gibbs free energy (ΔfG⦵)
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−580.1 kJ/mol |
Enthalpy of fusion (ΔfH⦵fus)
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86 kJ/mol |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards
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Very toxic, Group 1B carcinogen |
GHS labelling: | |
Danger | |
H301, H315, H317, H319, H330, H335, H350, H372 | |
P201, P260, P280, P284, P301+P310, P305+P351+P338 | |
NFPA 704 (fire diamond) | |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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15 mg/kg (mouse, oral)[11] |
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)[10] |
REL (Recommended)
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Ca C 0.0005 mg/m3 (as Be)[10] |
IDLH (Immediate danger) |
Ca [4 mg/m3 (as Be)][10] |
Related compounds | |
Other anions
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Beryllium telluride |
Other cations
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Supplementary data page | |
Beryllium oxide (data page) | |
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 oxide (BeO), also known as beryllia, is an inorganic compound with the formula BeO. This colourless solid is a notable electrical insulator with a higher thermal conductivity than any other non-metal except diamond, and exceeds that of most metals.[12] As an amorphous solid, beryllium oxide is white. Its high melting point leads to its use as a refractory material.[13] It occurs in nature as the mineral bromellite. Historically and in materials science, beryllium oxide was called glucina or glucinium oxide, owing to its sweet taste.
Preparation and chemical properties
Beryllium oxide can be prepared by calcining (roasting) beryllium carbonate, dehydrating beryllium hydroxide, or igniting metallic beryllium:
- BeCO3 → BeO + CO2
- Be(OH)2 → BeO + H2O
- 2 Be + O2 → 2 BeO
Igniting beryllium in air gives a mixture of BeO and the nitride Be3N2.[12] Unlike the oxides formed by the other Group 2 elements (alkaline earth metals), beryllium oxide is amphoteric rather than basic.
Beryllium oxide formed at high temperatures (>800 °C) is inert, but dissolves easily in hot aqueous ammonium bifluoride (NH4HF2) or a solution of hot concentrated sulfuric acid (H2SO4) and ammonium sulfate ((NH4)2SO4).
Structure
BeO crystallizes in the hexagonal
In the vapour phase, beryllium oxide is present as discrete
Applications
High-quality crystals may be grown
Beryllium oxide is used in many high-performance
Safety
BeO is carcinogenic in powdered form[19] and may cause a chronic allergic-type lung disease berylliosis. Once fired into solid form, it is safe to handle if not subjected to machining that generates dust. Clean breakage releases little dust, but crushing or grinding actions can pose a risk.[20]
References
- ^ "beryllium oxide – Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 27 March 2005. Identification and Related records. Retrieved 8 November 2011.
- ^ a b Haynes, p. 4.51
- .
- ^ Haynes, p. 4.126
- ^ Haynes, p. 12.222
- ^ Haynes, p. 10.248
- ^ Bromellite Mineral Data. webmineral
- ^ Haynes, p. 4.139
- ^ Haynes, pp. 5.1, 5.6, 6.155
- ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0054". National Institute for Occupational Safety and Health (NIOSH).
- ^ Beryllium oxide toxicity
- ^ ISBN 978-0-08-037941-8.
- ISBN 0-7506-6850-4.
- ISBN 0-19-855370-6.
- ISBN 978-81-7023-911-6. Retrieved 29 November 2011.
- ^ Greg Becker; Chris Lee; Zuchen Lin (2005). "Thermal conductivity in advanced chips — Emerging generation of thermal greases offers advantages". Advanced Packaging: 2–4. Archived from the original on June 21, 2000. Retrieved 2008-03-04.
- ^ McClure, Patrick; Poston, David; Gibson, Marc; Bowman, Cheryl; Creasy, John (14 May 2014). "KiloPower Space Reactor Concept – Reactor Materials Study". Retrieved 21 November 2017.
- ^ "Hazardous Substance Fact Sheet" (PDF). New Jersey Department of Health and Senior Services. Retrieved August 17, 2018.
- ^ "Beryllium Oxide Safety". American Beryllia. Retrieved 2018-03-29.
Cited sources
- Haynes, William M., ed. (2016). ISBN 9781498754293.