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Beryllium fluoride
IUPAC name	Berylium fluoride
Identifiers
CAS number	7787-49-7
PubChem	24589
RTECS number	DS2800000
SMILES	[Be+2].[F-].[F-]
InChI	1/Be.2FH/h;2*1H/q+2;;/p-2
InChI key	JZKFIPKXQBZXMW-NUQVWONBAD
ChemSpider ID	22992
Properties
Molecular formula	BeF2
Molar mass	47.01 g/mol; hygroscopic
Appearance	colorless lumps
Density	1.986 g/cm3
Melting point	554 °C, 827 K, 1029 °F
Boiling point	1169 °C, 1442 K, 2136 °F ()
Solubility in water	very soluble
Solubility	sparingly soluble in alcohol
Thermochemistry
Std enthalpy of; formation ΔfHo298	-21.84 kJ/g
Specific heat capacity, C	1.102 J/K
Hazards
EU Index	004-002-00-2
EU classification	Carc. Cat. 2; Highly toxic (T+); Irritant (Xi); Dangerous for the environment (N)
R-phrases	R49, R25, R26, R36/37/38, R43, R48/23, R51/53
S-phrases	S53, S45, S61
Flash point	non-flammable
LD50	98 mg/kg (oral, rat)
	(what is this?) (verify); Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
	Infobox references

Beryllium fluoride is the chemical compound with the formula BeF₂. It is the binary beryllium compound with the greatest amount of ionic character (due to the high electronegativity of fluorine), but even so it is not considered ionic by many chemists. This synthetic material is the principal precursor for the manufacture of beryllium metal, which is obtained by reduction of BeF₂ at 1300°C:^[2]

BeF₂ + Mg → Be + MgF₂

Solid crystalline BeF₂ has a silica-like structure with four coordinate beryllium.^[3] Molecular BeF₂, is isoelectronic with CO₂ and SiO₂ and as found in the gas-phase above 1160 °C is a linear molecule with a Be-F distance of 177 pm.^[2]. The condensed form adopts a number of different polymeric structures similar to those formed by SiO₂ namely α-quartz, β-quartz, crystobalite and tridymite,^[4]. The difference between the ambient temperature structures of BeF₂ and CO₂ reflects the decreased tendency of alkali metals to form multiple bonds. An analogy exists between BeF₂ and AlF₃: both adopt extended structures at mild temperature.

[edit] Applications

Beryllium fluoride is used in biochemistry, particularly protein crystallography, since it binds in some of the same ways as phosphate does. ADP and beryllium fluoride together tend to bind to ATP sites and inhibit protein action, making it possible to crystallise proteins in the bound state.^[5]

Beryllium fluoride forms a basic constituent of the preferred fluoride salt mixture used in liquid-fluoride nuclear reactors. Typically beryllium fluoride is mixed with lithium fluoride to form a base solvent, into which fluorides of uranium and thorium are introduced. Beryllium fluoride is exceptionally chemically stable and LiF/BeF2 mixtures have low melting points and the best neutronic properties of fluoride salt combinations appropriate for reactor use.

[edit] Safety

All beryllium compounds are highly toxic. Beryllium fluoride is very soluble in water and is thus absorbed easily; as mentioned above, it inhibits ATP uptake. The LD50 in mice is about 100mg/kg by ingestion and 1.8mg/kg by intravenous injection.

[edit] References

^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0070494398
^ ^a ^b Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
^ Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6
^ Greenwood, Norman N.; Earnshaw, A. (1997), Chemistry of the Elements (2nd ed.), Oxford: Butterworth-Heinemann, ISBN 0-7506-3365-4
^ Reiko Kagawa1, Martin G Montgomery, Kerstin Braig, Andrew G W Leslie and John E Walker (2004). "The structure of bovine F1-ATPase inhibited by ADP and beryllium fluoride". The EMBO Journal 23 (5): 2734–2744. doi:10.1038/sj.emboj.7600293.

from which the LD50 figures

[edit] External links

[0] Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0070494398

[Holl-1] Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.

[2] Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6

[3] Greenwood, Norman N.; Earnshaw, A. (1997), Chemistry of the Elements (2nd ed.), Oxford: Butterworth-Heinemann, ISBN 0-7506-3365-4

[4] Reiko Kagawa1, Martin G Montgomery, Kerstin Braig, Andrew G W Leslie and John E Walker (2004). "The structure of bovine F1-ATPase inhibited by ADP and beryllium fluoride". The EMBO Journal 23 (5): 2734–2744. doi:10.1038/sj.emboj.7600293.

[1]

[2]

[3]

[4]

[5]

Contents

[edit] Applications

[edit] Safety

[edit] References

[edit] External links