Beryllium chloride

Beryllium chloride is an inorganic compound with the formula BeCl2. It is a colourless, hygroscopic solid that dissolves well in many polar solvents. Its properties are similar to those of aluminium chloride, due to beryllium's diagonal relationship with aluminium.

Beryllium dichloride
Names
IUPAC name
Beryllium chloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.029.197
RTECS number
  • DS2625000
Properties
BeCl2
Molar mass 79.9182 g/mol
Appearance White or yellow crystals
Density 1.899 g/cm3, solid
Melting point 399 °C (750 °F; 672 K)
Boiling point 482 °C (900 °F; 755 K)
15.1 g/100 mL (20 °C)
Solubility soluble in alcohol, ether, benzene, and pyridine
slightly soluble in chloroform and sulfur dioxide
Structure
hexagonal
polymer
Thermochemistry
7.808 J/K or 71.1 J/mol K
63 J/mol K
−6.136 kJ/g or -494 kJ/mol
-468 kJ/mol
16 kJ/mol
Hazards
Lethal dose or concentration (LD, LC):
86 mg/kg (rat, oral)
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)[1]
REL (Recommended)
 Ca C 0.0005 mg/m3 (as Be)[1]
IDLH (Immediate danger)
 Ca [4 mg/m3 (as Be)][1]
Related compounds
Other anions
 Beryllium fluoride
Beryllium bromide
Beryllium iodide
Other cations
 Magnesium chloride
Calcium chloride
Strontium chloride
Barium chloride
Radium chloride
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

Structure and synthesis

Beryllium chloride is prepared by reaction of the metal with chlorine at high temperatures:[2]

Be + Cl2 → BeCl2

BeCl2 can also be prepared by carbothermal reduction of beryllium oxide in the presence of chlorine.[3] BeCl2 can be prepared by treating beryllium with hydrogen chloride.

The solid is a 1-dimensional polymer consisting of edge-shared tetrahedra.[4] In contrast, BeF2 is a 3-dimensional polymer, with a structure akin to that of quartz. In the gas phase, BeCl2 exists both as a linear monomer and a bridged dimer with two bridging chlorine atoms where the beryllium atom is 3-coordinate.[5] The linear shape of the monomeric form is as predicted by VSEPR theory. The linear shape contrasts with the monomeric forms of some of the dihalides of the heavier members of group 2, e.g. CaF2, SrF2, BaF2, SrCl2, BaCl2, BaBr2, and BaI2, which are all non-linear.[5]

Reactions

Beryllium chloride is stable in dry air. Beryllium chloride is a Lewis acid and has been used as a catalyst in some organic reactions. It hydrolyzes, evolving hydrogen chloride:

BeCl2 + 2H2O → Be(OH)2 + 2 HCl

It forms a tetrahydrate, BeCl2•4H2O ([Be(H2O)4]Cl2). BeCl2 is also soluble in oxygenated solvents such as ethers.[6][7]

Applications

Beryllium chloride is used as a raw material for the electrolysis of beryllium, and as a catalyst for Friedel-Crafts reactions.

References
  1. NIOSH Pocket Guide to Chemical Hazards. "#0054". National Institute for Occupational Safety and Health (NIOSH).
  2. Irving R. Tannenbaum "Beryllium Chloride" Inorganic Syntheses, 1957, vol. 5, p. 22. doi:10.1002/9780470132364.ch7
  3. Cotton, F. A.; Wilkinson, G. (1980) Advanced Inorganic Chemistry John Wiley and Sons, Inc: New York, ISBN 0-471-02775-8.
  4. Wells, A. F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
  5. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  6. Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3.
  7. Holleman, A. F.; Wiberg, E. (2001) Inorganic Chemistry Academic Press: San Diego, ISBN 0-12-352651-5
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