Beryllium chloride

Beryllium chloride
Names



IUPAC name Beryllium chloride
Identifiers
CAS Number	7787-47-5^Y
3D model (JSmol)	ionic depiction: Interactive image covalent monomer: Interactive image polymer: Interactive image
ChemSpider	22991^Y
ECHA InfoCard	100.029.197
PubChem CID	24588
RTECS number	DS2625000
UNII	58B7024067^Y
CompTox Dashboard (EPA)	DTXSID10858756
InChI InChI=1S/Be.2ClH/h;21H/q+2;;/p-2^Y Key: LWBPNIJBHRISSS-UHFFFAOYSA-L^Y 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 (S^⦵₂₉₈)	63 J/mol K
Std enthalpy of formation (Δ_fH^⦵₂₉₈)	−6.136 kJ/g or -494 kJ/mol
Gibbs free energy (Δ_fG^⦵)	-468 kJ/mol
Std enthalpy of combustion (Δ_cH^⦵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). N verify (what is ^YN ?) Infobox references

Chemical compound

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.

Two forms (polymorphs) of BeCl₂ are known. Both structures consist tetrahedral Be²⁺ centers interconnected by doubly bridging chloride ligands. One form consist of edge-sharing polytetrahedra. The other form resembles zinc iodide with interconnected adamantane-like cages.^[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] Beryllium chloride dissolves to give tetrahedral [Be(OH₂)₄]²⁺ ion in aqueous solutions as confirmed by vibrational spectroscopy.^[6]

Reactions

Beryllium chloride forms a tetrahydrate, BeCl₂•4H₂O ([Be(H₂O)₄]Cl₂). BeCl₂ is also soluble in some ethers.^[7]^[8]

Applications

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

References

^ ^a ^b ^c 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.
^ Troyanov, S.I. (2000). "Crystal Modifications of Beryllium Dihalides BeCl₂, BeBr₂ and BeI₂". Zhurnal Neorganicheskoi Khimii. 45: 1619-1624.
^ ^a ^b Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
^ Rudolph, Wolfram W.; Fischer, Dieter; Irmer, Gert; Pye, Cory C. (2009). "Hydration of Beryllium(II) in Aqueous Solutions of Common Inorganic Salts. A Combined Vibrational Spectroscopic and ab initio Molecular Orbital Study". Dalton Transactions (33): 6513–6527. doi:10.1039/B902481F. PMID 19672497.
^ 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