What is the form of BeCl2

Beryllium chloride

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Beryllium chloride is the beryllium salt of hydrochloric acid with the empirical formula BeCl2. The salt is used, among other things, for the production of metallic beryllium by fused-salt electrolysis.

Extraction and presentation

BeCl2 is technically produced from beryllium oxide, carbon and chlorine at approx. 800 ° C[6]:

$ \ mathrm {BeO + C + Cl_2 \ longrightarrow \ BeCl_2 + CO \ uparrow} $

Physical Properties

The Be-Cl bond has strong covalent bond components. Beryllium chloride therefore does not form an ion lattice like magnesium or calcium chloride, but a chain-like polymeric structure in which each beryllium nucleus is tetrahedrally surrounded by four chlorine atoms. The structure corresponds in its structure to the fibrous form of silicon dioxide.

Monomeric and dimeric BeCl are found in the gas phase2-Units in which the intrinsic electron deficiency at the beryllium atom is reduced by the partial double bond character of the Be-Cl bond. The bond length in the monomer is 170 pm.[7]

Structure of monomeric beryllium chloride

Chemical properties

Beryllium chloride dissolves in a strongly exothermic hydrolysis, whereby the aqueous solution reacts acidic.

$ \ mathrm {BeCl_2 + 4 \ H_2O \ \ rightleftharpoons \ [Be (H_2O) _4] ^ {2+} + 2 \ Cl ^ -} $

$ \ mathrm {[Be (H_2O) _4] ^ {2+} + H_2O \ \ rightleftharpoons \ H_3O ^ + + [Be (H_2O) _3 (OH)] ^ +} $

The tetraaquaberyllium cations react as Aqua acid and dissociate.

BeCl dissolves as a Lewis acid2 in donor solvents such as alcohols or ethers to form adducts. BeCl2 can accordingly be used as a catalyst in a Friedel-Crafts alkylation.

When melting with sodium in the absence of air, beryllium chloride is reduced to elemental beryllium.[8]

Individual evidence

  1. 1,01,11,21,31,4CD Römpp Chemie Lexikon - Version 1.0, Stuttgart / New York: Georg Thieme Verlag 1995
  2. 2,02,1 Not explicitly listed in EU Regulation (EC) 1272/2008 (CLP), but falls under the collective term there with the specified labeling “Beryllium Compounds”;Entry from the CLP regulation on beryllium compounds in the GESTIS substance database of the IFA, accessed on April 8, 2012 (JavaScript required) Reference error: Invalid tag. The name "CLP_82790" was defined several times with different content.
  3. ↑ data sheet Beryllium chloride at Sigma-Aldrich, accessed on March 13, 2011.
  4. ↑ Since December 1, 2012, only GHS hazardous substance labeling has been permitted for substances. Until June 1, 2015, the R-phrases of this substance can still be used to classify preparations, after which the EU hazardous substance labeling is of purely historical interest.
  5. ↑ entry to CAS no. 7787-47-5 in the GESTIS substance database of the IFA, accessed on March 13, 2011 (JavaScript required).
  6. ↑ Harry H. Binder: Lexicon of the chemical elements, S. Hirzel Verlag, Stuttgart 1999, ISBN 3-7776-0736-3.
  7. ↑ Holleman, Wiberg, Inorganic Chemistry Textbook, P. 1108f, 101st edition, 1995, deGruyter Verlag.
  8. ↑ L. F. Nilson, O. Petterssen: "About the specific heat of beryllium" in Reports of the German Chemical Society1878, 11, Pp. 381-386. Full text

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