Beryllium chloride

Summary

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 chloride
BeCl2polymer.png
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EntryWithCollCode92587.png
Names
IUPAC name
Beryllium chloride
Identifiers
  • 7787-47-5 checkY
3D model (JSmol)
  • ionic depiction: Interactive image
  • covalent monomer: Interactive image
  • polymer: Interactive image
ChemSpider
  • 22991 checkY
ECHA InfoCard 100.029.197 Edit this at Wikidata
  • 24588
RTECS number
  • DS2625000
UNII
  • 58B7024067 checkY
  • DTXSID10858756 Edit this at Wikidata
  • InChI=1S/Be.2ClH/h;2*1H/q+2;;/p-2 checkY
    Key: LWBPNIJBHRISSS-UHFFFAOYSA-L checkY
  • InChI=1/Be.2ClH/h;2*1H/q+2;;/p-2
    Key: LWBPNIJBHRISSS-NUQVWONBAX
  • 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
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 synthesisEdit

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]

ReactionsEdit

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

ApplicationsEdit

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

ReferencesEdit

  1. ^ a b c 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. ^ Troyanov, S.I. (2000). "Crystal Modifications of Beryllium Dihalides BeCl2, BeBr2 and BeI2". Zhurnal Neorganicheskoi Khimii. 45: 1619-1624.
  5. ^ a b Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  6. ^ 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.
  7. ^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3.
  8. ^ Holleman, A. F.; Wiberg, E. (2001) Inorganic Chemistry Academic Press: San Diego, ISBN 0-12-352651-5

External linksEdit

  • Properties of BeCl2 from NIST