Script assisted update of identifiers from ChemSpider, CommonChemistry and FDA for the Chem/Drugbox validation project - Updated: InChI1 InChIKey1 SMILES. |
Script assisted update of identifiers from ChemSpider, CommonChemistry and FDA for the Chem/Drugbox validation project - Updated: InChI1->InChI StdInChI StdInChIKey. |
||
| Line 5: | Line 5: | ||
| ImageName = |
| ImageName = |
||
| Section1 = {{Chembox Identifiers |
| Section1 = {{Chembox Identifiers |
||
| |
| InChI = 1/Be.2H/rBeH2/h1H2 |
||
| |
| InChIKey = RWASOQSEFLDYLC-JICJMJRQAQ |
||
| SMILES = [BeH2] |
| SMILES = [BeH2] |
||
| StdInChI = 1S/Be.2H |
|||
| StdInChIKey = RWASOQSEFLDYLC-UHFFFAOYSA-N |
|||
| CASNo = 7787-52-2 |
| CASNo = 7787-52-2 |
||
| PubChem = 139073 |
| PubChem = 139073 |
||
Revision as of 16:31, 29 November 2010
| |
| Identifiers | |
|---|---|
3D model (JSmol)
|
|
| ChemSpider | |
PubChem CID
|
|
| |
| |
| Properties | |
| BeH2 | |
| Molar mass | 11.03 g mol−1 |
| Appearance | amorphous white solid[1] |
| Density | 0.65 g/cm3 |
| Melting point | 250 °C with decomp.[1] |
| decomposes | |
| Related compounds | |
Other cations
|
lithium hydride, calcium hydride, boron hydrides |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
| |
Beryllium hydride, BeH2, is a chemical compound of beryllium and hydrogen commonly used in rocket fuel [2]. Unlike the ionically bonded hydrides of the heavier Group 2 elements, beryllium hydride is covalently bonded.[1]
Synthesis
BeH2 was first synthesised in 1951 by reacting dimethylberyllium, Be(CH3)2, with lithium aluminium hydride, LiAlH4[3].
Purer BeH2 forms from the pyrolysis of di-tert-butylberyllium, Be(C(CH3)3)2 at 210 °C[4].
The purest beryllium hydride is obtained by the reaction of triphenylphosphine, PPh3, with beryllium borohydride, Be(BH4)2[1]:
- Be(BH4)2 + 2PPh3 → 2Ph3PBH3 + BeH2
Note that unlike the other elements in group 2 where the hydride can be prepared by reaction of the elements, the reaction of the metal with hydrogen to produce beryllium hydride has not proved possible.[5]
Structure
BeH2 is usually formed as an amorphous white solid, but a hexagonal crystalline form with a higher density (~0.78 g cm−3) was reported[6], prepared by heating amorphous BeH2 under pressure, with 0.5-2.5% LiH as a catalyst.
A more recent investigation found that crystalline beryllium hydride has a body-centred orthorhombic unit cell, containing a network of corner-sharing BeH4 tetrahedra, in contrast to the flat, hydrogen-bridged, infinite chains previously thought to exist in crystalline BeH2[7].
Studies of the amorphous form also find that it consists of a network of corner shared tetrahedra.[8]
Molecular BeH2 has been confirmed in a recent study as linear with a Be-H bond length of 133.376 pm. [9]
References
- ^ a b c d Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8., p. 115
- ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0070494398
- ^ Glenn D. Barbaras, Clyde Dillard, A. E. Finholt, Thomas Wartik, K. E. Wilzbach, and H. I. Schlesinger (1951). "The Preparation of the Hydrides of Zinc, Cadmium, Beryllium, Magnesium and Lithium by the Use of Lithium Aluminum Hydride". J. Am. Chem. Soc. 73 (10): 4585–4590. doi:10.1021/ja01154a025.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ G. E. Coates and F. Glockling (1954). "Di-tert.-butylberyllium and beryllium hydride". J. Chem. Soc.: 2526–2529. doi:10.1039/JR9540002526.
- ^ Egon Wiberg, Arnold Frederick Holleman (2001) Inorganic Chemistry, Elsevier ISBN 0123526515, p. 1048
- ^ G. J. Brendel, E. M. Marlett, and L. M. Niebylski (1978). "Crystalline beryllium hydride". Inorg. Chem. 17 (12): 3589–3592. doi:10.1021/ic50190a051.
{{cite journal}}: Cite has empty unknown parameter:|1=(help)CS1 maint: multiple names: authors list (link) - ^ Gordon S. Smith, Quintin C. Johnson, Deane K. Smith, D. E. Cox, Robert L. Snyder, Rong-Sheng Zhou and Allan Zalkin (1988). "The crystal and molecular structure of beryllium hydride". Solid State Communications. 67 (5): 491–494. doi:10.1016/0038-1098(84)90168-6.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Sujatha Sampath, Kristina M. Lantzky, Chris J. Benmore, Jörg Neuefeind, and Joan E. Siewenie (2003). "Structural quantum isotope effects in amorphous beryllium hydride". J. Chem. Phys. 119: 12499. doi:10.1063/1.1626638.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Peter F. Bernath, Alireza Shayesteh, Keith Tereszchuk, Reginald Colin (2002). "The Vibration-Rotation Emission Spectrum of Free BeH2". Science. 297 (5585): 1323–1324. doi:10.1126/science.1074580. PMID 12193780.
{{cite journal}}: CS1 maint: multiple names: authors list (link)