Beryllium chloride

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Beryllium dichloride
Beryllium-chloride-xtal-3D-balls-A.png
Identifiers
CAS number 7787-47-5 N
PubChem 24588
ChemSpider 22991 YesY
RTECS number DS2625000
Jmol-3D images Image 1
Properties
Molecular formula 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)
Solubility in water 15.1 g/100 mL (20 °C)
Solubility soluble in alcohol, ether, benzene, and pyridine
slightly soluble in chloroform and sulfur dioxide
Structure
Crystal structure hexagonal
Molecular shape polymer
Thermochemistry
Specific
heat capacity
C
7.808 J/K or 71.1 J/mol K
Std molar
entropy
So298
63 J/mol K
Std enthalpy of
formation
ΔfHo298
−6.136 kJ/g or -494 kJ/mol
Gibbs free energy ΔG -468 kJ/mol
Std enthalpy of
combustion
ΔcHo298
16 kJ/mol
Hazards
LD50 86 mg/kg (rat, oral)
Related compounds
Other anions Beryllium fluoride
Beryllium bromide
Beryllium iodide
Other cations Magnesium chloride
Calcium chloride
Strontium chloride
Barium chloride
Radium chloride
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

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.

Structure and synthesis[edit]

Beryllium chloride is prepared by reaction of the metal with chlorine at high temperatures:[1]

Be + Cl2 → BeCl2

BeCl2 can also be prepared by carbothermal reduction of beryllium oxide in the presence of chlorine.[2] BeCl2 can be prepared by treating Be metal with hydrogen chloride.

BeCl2

The solid is a 1-dimensional polymer consisting of edge-shared tetrahedra.[3] In contrast, BeF2 is a 3-dimensional polymer, with a structure akin to that of quartz. In the gas phase, it exists both as a linear monomer and a bridged dimer with two bridging chlorine atoms where the beryllium atom is 3-coordinate.[4] 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.[4]

Reactions[edit]

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.[5][6]

Applications[edit]

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

References[edit]

  1. ^ Irving R. Tannenbaum "Beryllium Chloride" Inorganic Syntheses, 1957, vol. 5, p. 22. doi:10.1002/9780470132364.ch7
  2. ^ Cotton, F. A.; Wilkinson, G. (1980) Advanced Inorganic Chemistry John Wiley and Sons, Inc: New York, ISBN 0-471-02775-8.
  3. ^ Wells, A. F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
  4. ^ a b Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0080379419. 
  5. ^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3. 
  6. ^ Holleman, A. F.; Wiberg, E. (2001) Inorganic Chemistry Academic Press: San Diego, ISBN 0-12-352651-5

External links[edit]