Beryllium hydride

Structural formula
General
Surname	Beryllium hydride
other names	Beryllium hydrogen
Molecular formula	BeH 2
Brief description	White dust
External identifiers / databases
PubChem	139073
Wikidata	Q417304
properties
Molar mass	11.03 g / mol
Physical state	firmly
density	0.65 g cm −3 (25 ° C)
Melting point	from 240 ° C decomposition into the components
safety instructions
H and P phrases	H: 350i-330-301-372-319-335-315-317-411
	P: ?
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Beryllium hydride is a chemical compound consisting of the elements beryllium and hydrogen . It has the empirical formula BeH ₂ and belongs to the group of hydrides .

presentation

The representation of beryllium hydride from the elements beryllium and hydrogen is not possible. It is expedient to obtain from an organometallic beryllium compound and a hydride such as lithium aluminum hydride (LiAlH ₄ ) or diborane . The reaction is carried out in diethyl ether , since the product beryllium hydride is not soluble in ether and precipitates out of solution.

{\ displaystyle \ mathrm {2 \ Be (CH_ {3}) _ {2} + LiAlH_ {4} \ rightarrow 2 \ BeH_ {2} + LiAl (CH_ {3}) _ {4}}}

It is also possible to prepare beryllium hydride by thermolysis of bis ( tert- butyl) beryllium at 210 ° C:

{\ displaystyle \ mathrm {Be (C_ {4} H_ {9}) _ {2} \ rightarrow BeH_ {2} +2 \ H_ {2} C \ operatorname {=} C (CH_ {3}) _ {2 }}}

Beryllium hydride can also be prepared from the complex beryllium borohydride - etherate .

{\ displaystyle \ mathrm {Be (BH_ {4}) _ {2} \ cdot (C_ {2} H_ {5}) _ {2} O + \ 2 \ (C_ {6} H_ {5}) _ {3 } P \ rightarrow BeH_ {2} + \ 2 \ (C_ {6} H_ {5}) _ {3} P \ cdot BH_ {3} + (C_ {2} H_ {5}) _ {2} O} }

properties

Beryllium hydride is a solid, white, non-volatile, highly polymeric substance that breaks down into its elements between 205 and 250 ° C. It is sensitive to moisture and air and is insoluble in most organic solvents . In water it decomposes to form beryllium hydroxide .

{\ displaystyle \ mathrm {BeH_ {2} +2 \ H_ {2} O \ longrightarrow \ Be (OH) _ {2} +2 \ H_ {2}}}

Beryllium hydride forms a chain-like polymer in which each beryllium core is tetrahedrally surrounded by four hydrogens. It forms a structure similar to that of aluminum hydride with covalent three-center bonds .

Spatial structure of polymeric beryllium hydride

use

Beryllium hydride is used as a rocket fuel and as a moderator in nuclear reactors .

Individual evidence

↑ ^a ^b Kenneth A. Walsh: "Beryllium chemistry and processing", ASM International (2009). P. 121 ( limited preview in Google Book search).
^ Carl L. Yaws: "Thermophysical Properties of Chemicals and Hydrocarbons", p. 298. ( limited preview in Google book search).
^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 .
↑ Entry on beryllium compounds in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
↑ Not explicitly listed in Regulation (EC) No. 1272/2008 (CLP) , but with the indicated labeling it falls under the group entry beryllium compounds with the exception of aluminum beryllium silicates, and with those specified elsewhere in this Annex in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
↑ ^a ^b Georg Brauer (Ed.), With the collaboration of Marianne Baudler u a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , p. 890.
↑ Hans Zimmer: Annual Reports in Inorganic and General Syntheses-1976 . Elsevier, 2016, ISBN 978-1-4832-8159-9 , pp. 2 ( limited preview in Google Book search).
^ CH Bamford, CFH Tipper: Reactions in the Solid State . Elsevier, 1980, ISBN 0-444-41807-5 , pp. 155 ( limited preview in Google Book search).
^ Dale L. Perry, Sidney L. Phillips: Handbook of inorganic compounds . CRC Press, 1995, ISBN 978-0-8493-8671-8 , p. 62 ( limited preview in Google book search).

[Walsh-1] Kenneth A. Walsh: "Beryllium chemistry and processing", ASM International (2009). P. 121 ( limited preview in Google Book search).

[Yaws-2] Carl L. Yaws: "Thermophysical Properties of Chemicals and Hydrocarbons", p. 298. ( limited preview in Google book search).

[HoWi-3] AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 .

[GESTIS-4] Entry on beryllium compounds in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .

[CLP_100.240.756-5] Not explicitly listed in Regulation (EC) No. 1272/2008 (CLP) , but with the indicated labeling it falls under the group entry beryllium compounds with the exception of aluminum beryllium silicates, and with those specified elsewhere in this Annex in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[brauer-6] Georg Brauer (Ed.), With the collaboration of Marianne Baudler u a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , p. 890.

[Hans_Zimmer-7] Hans Zimmer: Annual Reports in Inorganic and General Syntheses-1976 . Elsevier, 2016, ISBN 978-1-4832-8159-9 , pp. 2 ( limited preview in Google Book search).

[Bamford-8] CH Bamford, CFH Tipper: Reactions in the Solid State . Elsevier, 1980, ISBN 0-444-41807-5 , pp. 155 ( limited preview in Google Book search).

[perry-9] Dale L. Perry, Sidney L. Phillips: Handbook of inorganic compounds . CRC Press, 1995, ISBN 978-0-8493-8671-8 , p. 62 ( limited preview in Google book search).