Beryllium hydroxide

Beryllium hydroxide, Be(OH)2, is an amphoteric hydroxide, dissolving in both acids and alkalis. Industrially, it is produced as a by-product in the extraction of beryllium metal from the ores beryl and bertrandite.[4] The natural pure beryllium hydroxide is rare (in form of the mineral behoite, orthorhombic) or very rare (clinobehoite, monoclinic).[5][6] When alkali is added to beryllium salt solutions the α-form (a gel) is formed. If this left to stand or boiled, the rhombic β-form precipitates.[7] This has the same structure as zinc hydroxide, Zn(OH)2, with tetrahedral beryllium centers.[8]

Beryllium hydroxide
Names
IUPAC name
Beryllium hydroxide
Other names
Hydrated beryllia
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.033.048
EC Number
  • 236-368-6
1024
MeSH Beryllium+hydroxide
RTECS number
  • DS3150000
UNII
Properties
BeH2O2
Molar mass 43.026 g·mol−1
Appearance Vivid white, opaque crystals
Density 1.92 g cm−3[1]
Melting point (decomposes)
0.0000023965 g/L
Structure
Linear
Thermochemistry
1.443 J K−1
47 J·mol−1·K−1[2]
Std enthalpy of
formation (ΔfH⦵298)
 -904 kJ mol−1[2]
-818 kJ/mol
Hazards
Main hazards Carcinogenic
GHS pictograms
GHS Signal word Danger
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 4: Very short exposure could cause death or major residual injury. E.g. VX gasReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
4
0
Lethal dose or concentration (LD, LC):
4 mg kg−1 (intravenous, rat)
NIOSH (US health exposure limits):
PEL (Permissible)
 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)
 Ca C 0.0005 mg/m3 (as Be)[3]
IDLH (Immediate danger)
 Ca [4 mg/m3 (as Be)][3]
Related compounds
Related compounds
 Aluminium oxide

Magnesium hydroxide

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Reactions

Beryllium hydroxide is difficult to dissolve in water. With alkalis it dissolves to form the tetrahydroxoberyllate/tetrahydroxidoberyllate anion, [Be(OH)4]2−.[9] With sodium hydroxide solution:

2NaOH(aq) + Be(OH)2(s) → Na2Be(OH)4(aq)

With acids, beryllium salts are formed.[9] For example, with sulfuric acid, H2SO4, beryllium sulfate is formed:

Be(OH)2 + H2SO4 → BeSO4 + 2H2O

Beryllium hydroxide dehydrates at 400 °C to form the soluble white powder, beryllium oxide:[9]

Be(OH)2 → BeO + H2O

Further heating at higher temperature produces acid insoluble BeO.[9]

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References
  1. Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  2. Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. ISBN 0-618-94690-X.
  3. NIOSH Pocket Guide to Chemical Hazards. "#0054". National Institute for Occupational Safety and Health (NIOSH).
  4. Jessica Elzea Kogel, Nikhil C. Trivedi, James M. Barker and Stanley T. Krukowski, 2006, Industrial Minerals & Rocks: Commodities, Markets, and Uses, 7th edition, SME, ISBN 0-87335-233-5
  5. Mindat, http://www.mindat.org/min-603.html
  6. Mindat, http://www.mindat.org/min-1066.html
  7. Mary Eagleson, 1994, Concise encyclopedia chemistry, Walter de Gruyter, ISBN 3-11-011451-8
  8. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  9. Egon Wiberg, Arnold Frederick Holleman (2001) Inorganic Chemistry, Elsevier ISBN 0-12-352651-5
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