Beryllium chloride

Structural formula
General
Surname	Beryllium chloride
other names	Chlorberyllium
Molecular formula	BeCl 2
Brief description	sweet-tasting, colorless, flowing crystals
External identifiers / databases
CAS number 7787-47-5 EC number 232-116-4 ECHA InfoCard 100.029.197 PubChem 24588 ChemSpider 22991 Wikidata Q265407
properties
Molar mass	79.92 g mol −1
Physical state	firmly
density	1.9 g cm −3
Melting point	405 ° C
boiling point	482 ° C
Sublimation point	300 ° C in a vacuum
solubility	Easily soluble in water, ethanol and other organic solvents
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 301-330-315-317-319-335-350i-372-411 P: 201-260-273-280-284-301 + 310
Toxicological data	86 mg kg −1 ( LD 50 ,  rat ,  oral ) 92 mg kg −1 ( LD 50 ,  mouse ,  oral )
Thermodynamic properties
ΔH f 0	−490.4 kJ / mol
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Beryllium chloride is the beryllium salt of hydrochloric acid with the empirical formula BeCl ₂ . The salt is used, among other things, for the production of metallic beryllium by fused- salt electrolysis .

Extraction and presentation

BeCl ₂ is technically produced from beryllium oxide , carbon and chlorine at approx. 800 ° C:

${\displaystyle \mathrm {BeO+C+Cl_{2}\longrightarrow \ BeCl_{2}+CO\uparrow } }$

Small amounts of the pure compound can be produced in the laboratory via direct synthesis from the elements at 350 ° C and subsequent sublimation of the chloride:

${\displaystyle {\ce {Be + Cl2 -> BeCl2}}}$

Physical Properties

The Be-Cl bond has strongly covalent bond components. Beryllium chloride therefore does not form an ion lattice such as magnesium or calcium chloride , but a chain-like polymer 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 .

In the gas phase there are monomeric and dimeric BeCl ₂ units, in which the intrinsic electron deficiency at the beryllium atom is reduced by the partial double bond character of the BeCl bond. The bond length in the monomer is 170 pm .

Structure of monomeric beryllium chloride

Chemical properties

Beryllium chloride is very hygroscopic . It goes into solution in a strongly exothermic hydrolysis, whereby the aqueous solution reacts acidic.

${\displaystyle \mathrm {BeCl_{2}+4\ H_{2}O\ \rightleftharpoons \ [Be(H_{2}O)_{4}]^{2+}+2\ Cl^{-}} }$

${\displaystyle \mathrm {[Be(H_{2}O)_{4}]^{2+}+H_{2}O\ \rightleftharpoons \ H_{3}O^{+}+[Be(H_{2}O)_{3}(OH)]^{+}} }$

The tetraaquaberyllium cations react as aqua acid and dissociate.

As a Lewis acid , BeCl _{2 dissolves} in donor solvents such as. B. alcohols or ethers, whereby adducts are formed. Accordingly, BeCl ₂ can be used as a catalyst in a Friedel-Crafts alkylation .

Beryllium chloride is reduced to elemental beryllium when melting with sodium in the absence of air.

use

The reaction of anhydrous beryllium chloride with anhydrous formic acid produces beryllium formate with the evolution of hydrogen chloride .

${\displaystyle \mathrm {BeCl_{2}+2\ HCOOH\longrightarrow Be(HCOO)_{2}+2\ HCl\uparrow } }$

Individual evidence

1. ↑ ^{a b c d e} Entry on beryllium compounds. In: Römpp Online . Georg Thieme Verlag, accessed on June 13, 2014.
2. ↑ ^{a b} Irving R. Tannenbaum: Beryllium chloride . In: Therald Moeller (Ed.): Inorganic Syntheses . tape 5 . McGraw-Hill, Inc., 1957, pp. 22-25 (English).
3. ↑ ^{a b c} Entry on beryllium chloride in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
4. ↑ Not explicitly listed in Regulation (EC) No. 1272/2008 (CLP) , but with the specified labeling it falls under the group entry beryllium compounds, with the exception of beryllium alumina silicates, and with the exception of those named in this annex in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on January 9, 2017. Manufacturers or distributors can expand the harmonized classification and labeling .
5. ^ Hygiene and Sanitation. Vol. 30 (1-3), pp. 169, 1965.
6. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-6.
7. ^ Harry H. Binder: Lexicon of the chemical elements , S. Hirzel Verlag, Stuttgart 1999, ISBN 3-7776-0736-3 .
8. ^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 , p. 1108.
9. ↑ LF Nilson, O. Petterssen: About the specific heat of beryllium . In: Reports of the German Chemical Society 1878 , 11 , pp. 381–386. ( Digitized on Gallica )
10. ↑ H. Funk, F. Römer: "About the reaction of some anhydrous chlorides with anhydrous acetic acid and formic acid" in Zeitschrift für inorganic und Allgemeine Chemie 1938 , 239 (3), pp. 288-294. doi : 10.1002 / zaac.19382390308
11. ^ GB Feild: "Reactions of Beryllium Chloride. Normal and Basic Organic Salts of Beryllium" in J. Am. Chem. Soc. 1939 , 61 (7), pp. 1817-1820 doi : 10.1021 / ja01876a050

Web links

• Video: Making Beryllium Chloride

Commons : Beryllium Chloride  - Collection of Pictures, Videos, and Audio Files