Beryllium chloride

Beryllium dichloride
Names
	IUPAC name Beryllium chloride
Identifiers
CAS Number	7787-47-5 ;
3D model (JSmol)	ionic depiction: Interactive image; covalent monomer: Interactive image; polymer: Interactive image;
ChemSpider	22991 ;
ECHA InfoCard	100.029.197
PubChem CID	24588;
RTECS number	DS2625000;
UNII	58B7024067 ;
CompTox Dashboard (EPA)	DTXSID10858756 ;
	InChI InChI=1S/Be.2ClH/h;21H/q+2;;/p-2 Key: LWBPNIJBHRISSS-UHFFFAOYSA-L ; InChI=1/Be.2ClH/h;21H/q+2;;/p-2 Key: LWBPNIJBHRISSS-NUQVWONBAX;
	SMILES ionic depiction: [Be+2].[Cl-].[Cl-]; covalent monomer: Cl[Be]Cl; polymer: Cl[Be-2](Cl)([Cl+]1)[Cl+][Be-2]1([Cl+]1)[Cl+][Be-2]1([Cl+]1)[Cl+][Be-2]1([Cl+]1)[Cl+][Be-2]1([Cl+]1)[Cl+][Be-2]1([Cl+]1)[Cl+][Be-2]1([Cl+]1)[Cl+][Be-2]1([Cl+]1)[Cl+][Be-2]1([Cl+]1)[Cl+][Be-2]1([Cl+]1)[Cl+][Be-2]1([Cl+]1)[Cl+][Be-2]1([Cl+]1)[Cl+][Be-2]1(Cl)Cl;
Properties
Chemical 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
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 (ΔfH⦵298)	−6.136 kJ/g or -494 kJ/mol
Gibbs free energy (ΔfG˚)	-468 kJ/mol
Std enthalpy of; combustion (ΔcH⦵298)	16 kJ/mol
Hazards
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	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

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

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.

Toxicity

Like all beryllium compounds, BeCl₂ is highly toxic.

References

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

External links

Beryllium chloride at IPCS INTOX databank
Properties of BeCl₂ from NIST

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[PGCH-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

[Cotton-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.

[Greenwood-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