Barium fluoride

Short description: Chemical compound

Barium fluoride

Identifiers

CAS Number

* 7787-32-8 Y

3D model (JSmol)

* Interactive image
* Interactive image

ChemSpider |

* 56421 Y

PubChem CID

* 62670

RTECS number |

* CQ9100000

UNII |

* H96A02I53Y Y

InChI

* InChI=1S/Ba.2FH/h;2*1H/q+2;;/p-2 Y

Key: OYLGJCQECKOTOL-UHFFFAOYSA-L Y

SMILES

* F[Ba]F

* [Ba+2].[F-].[F-]

Properties

Chemical formula

| BaF

Molar mass | 175.324 g/mol[1]
Appearance  | white cubic crystals[1]
Density | 4.893 g/cm3[1]
Melting point |  1,368 °C (2,494 °F; 1,641 K)[1]
Boiling point |  2,260 °C (4,100 °F; 2,530 K)[1]

Solubility in water

| 1.58 g/L (10 °C)
1.61 g/L (25 °C)[2]

Solubility product (Ksp)

| 1.84·10−7[3]
Solubility | soluble in methanol, ethanol

Magnetic susceptibility (χ)

| −51·10−6 cm3/mol[4]
Thermal conductivity | 10.9 W/(m·K)[5]

Refractive index (nD)

* 1.557 (200 nm)
* 1.4744 (589 nm)
* 1.4014 (10 µm)

[6]
Structure[7]

Crystal structure

| Fluorite (cubic), cF12

Space group

| Fm3m, No. 225

Lattice constant

a = 0.62 nm

Formula units (Z)

| 4
Thermochemistry[8]

Heat capacity (C)

| 71.2 J/(mol·K)

Std molar
entropy (S ~~o~~ 298)

| 96.4 J/(mol·K)

Std enthalpy of
formation (ΔfH⦵298)

| −1207.1 kJ/mol

Gibbs free energy (ΔfG˚)

| −1156.8 kJ/mol
Hazards
Main hazards | Toxic
Safety data sheet | PubChem
GHS pictograms |
Flash point | Non-flammable
Lethal dose or concentration (LD, LC):

LD50 (median dose)

| 250 mg/kg, oral (rat)
Related compounds

Other anions

* Barium chloride
* Barium bromide
* Barium iodide

Other cations

* Beryllium fluoride
* Magnesium fluoride
* Calcium fluoride
* Strontium fluoride
* Radium fluoride

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

N verify (what is YN ?)
Infobox references

Barium fluoride is an inorganic compound with the formula BaF
2. It is a colorless solid that occurs in nature as the rare mineral frankdicksonite.[9] Under standard conditions it adopts the fluorite structure and at high pressure the PbCl
2 structure.[10] Like CaF
2, it is resilient to and insoluble in water.

Above ca. 500 °C, BaF
2 is corroded by moisture, but in dry environments it can be used up to 800 °C. Prolonged exposure to moisture degrades transmission in the vacuum UV range. It is less resistant to water than calcium fluoride, but it is the most resistant of all the optical fluorides to high-energy radiation, though its far ultraviolet transmittance is lower than that of the other fluorides. It is quite hard, very sensitive to thermal shock and fractures quite easily.

## Contents

* 1 Optical properties
* 2 Gas phase structure
* 3 References
* 4 Cited sources
* 5 External links

## Optical properties

Barium fluoride is transparent from the ultraviolet to the infrared, from 150 to 200 nm to 11–11.5 µm. It is used in windows for infrared spectroscopy, in particular in the field of fuel oil analysis. Its transmittance at 200 nm is relatively low (0.60), but at 500 nm it goes up to 0.96–0.97 and stays at that level until 9 µm, then it starts falling off (0.85 for 10 µm and 0.42 for 12 µm). The refractive index is about 1.46 from 700 nm to 5 µm.[11]

Barium fluoride is also a common, very fast (one of the fastest) scintillators for the detection of X-rays, gamma rays or other high energy particles. One of its applications is the detection of 511 keV gamma photons in positron emission tomography. It responds also to alpha and beta particles, but, unlike most scintillators, it does not emit ultraviolet light.[12] It can be also used for detection of high-energy (10–150 MeV) neutrons, using pulse shape discrimination techniques to separate them from simultaneously occurring gamma photons.

Barium fluoride is used as a preopacifying agent and in enamel and glazing frits production. Its other use is in the production of welding agents (an additive to some fluxes, a component of coatings for welding rods and in welding powders). It is also used in metallurgy, as a molten bath for refining aluminium.

## Gas phase structure

In the vapor phase the BaF
2 molecule is non-linear with an F-Ba-F angle of approximately 108°.[13] Its nonlinearity violates VSEPR theory. Ab initio calculations indicate that contributions from d orbitals in the shell below the valence shell are responsible.[14] Another proposal is that polarisation of the electron core of the barium atom creates an approximately tetrahedral distribution of charge that interacts with the Ba-F bonds.[15]

## References

1. ↑ 1.0 1.1 1.2 1.3 1.4 Haynes, p. 4.49
2. ↑ Haynes, p. 5.167
3. ↑ John Rumble (June 18, 2018) (in English). CRC Handbook of Chemistry and Physics (99th ed.). CRC Press. pp. 4–47. ISBN 978-1138561632.
4. ↑ Haynes, p. 4.126
5. ↑ Haynes, p. 12.222
6. ↑ Haynes, p. 10.248
7. ↑ Hohnke, D. K.; Kaiser, S. W. (1974). "Epitaxial PbSe and Pb1−xSxSe: Growth and electrical properties". Journal of Applied Physics 45 (2): 892–897. doi:10.1063/1.1663334. Bibcode: 1974JAP....45..892H.
8. ↑ Haynes, p. 5.5
9. ↑ Radtke A.S., Brown G.E. (1974). "Frankdicksonite, BaF2, a New Mineral from Nevada". American Mineralogist 59: 885–888. http://www.minsocam.org/ammin/AM59/AM59_885.pdf.
10. ↑ Wells, A.F. (1984). Structural inorganic chemistry −5th Edition. Oxford: Clarendon Press. ISBN 0-19-855370-6.
11. ↑ "Crystran Ltd. Optical Component Materials". http://www.crystran.co.uk/barium-fluoride-baf2.htm.
12. ↑ Laval, M; Moszyński, M.; Allemand, R.; Cormoreche, E.; Guinet, P.; Odru, R.; Vacher, J. (1983). "Barium fluoride – Inorganic scintillator for subnanosecond timing". Nuclear Instruments and Methods in Physics Research 206 (1–2): 169–176. doi:10.1016/0167-5087(83)91254-1. Bibcode: 1983NIMPR.206..169L.
13. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
14. ↑ Seijo, Luis; Barandiarán, Zoila; Huzinaga, Sigeru (1991). "Ab initio model potential study of the equilibrium geometry of alkaline earth dihalides: MX2 (M=Mg, Ca, Sr, Ba; X=F, Cl, Br, I)". The Journal of Chemical Physics 94 (5): 3762. doi:10.1063/1.459748. Bibcode: 1991JChPh..94.3762S. https://repositorio.uam.es/bitstream/10486/7315/1/41581_jchemphysseijo_91_jcp_94_3762.pdf.
15. ↑ Bytheway, Ian; Gillespie, Ronald J.; Tang, Ting-Hua; Bader, Richard F. W. (1995). "Core Distortions and Geometries of the Difluorides and Dihydrides of Ca, Sr, and Ba". Inorganic Chemistry 34 (9): 2407. doi:10.1021/ic00113a023.

## Cited sources

* Haynes, William M., ed (2016). CRC Handbook of Chemistry and Physics (97th ed.). CRC Press. p. 4.49. ISBN 9781498754293.

## External links

* MSDS at Oxford University

* v
* t
* e

Barium compounds

* Ba(BO2)2
* BaBr2
* Ba(CH3CO2)2
* Ba(C5H7O2)2
* Ba(ClO)2
* Ba(ClO2)2
* BaCO3
* BaC2O4
* Ba(ClO3)2
* Ba(ClO4)2
* Ba(CN)2
* BaCl2
* BaCrO4
* BaF2
* BaFeO4
* BaFe2O4
* BaI2
* Ba(IO3)2
* Ba(Mn2O8)
* Ba(N3)2
* Ba(NO3)2
* BaO
* BaO2
* Ba(OH)2
* BaS
* BaSO3
* BaSO4
* BaTiO3
* Ba2TiO4

* v
* t
* e

Fluorine compounds

| HF |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | He

|
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LiF | BeF2 |  |  |  |  |  |  |  |  |  |  | BF3
B2F4 | CF4 | NF3 | OF2 | F− | Ne
NaF | MgF2 |  |  |  |  |  |  |  |  |  |  | AlF3 | SiF4 | PF3
PF5 | SF2
SF4
SF6 | ClF
ClF3
ClF5 | Ar
KF | CaF2 | ScF3 | TiF3
TiF4 | VF3
VF4
VF5 | CrF2
CrF3
CrF4
CrF5 | MnF2
MnF3 | FeF2
FeF3 | CoF2
CoF3 | NiF2 | CuF
CuF2 | ZnF2 | GaF3 | GeF4 | AsF3
AsF5 | SeF4
SeF6 | BrF3
BrF5 | KrF2
RbF | SrF2 | YF3 | ZrF4 | NbF4
NbF5 | MoF5
MoF6 | TcF6 | RuF3
RuF4
RuF5
RuF6 | RhF6 | PdF2 | AgF
AgF2
Ag2F | CdF2 | InF3 | SnF2
SnF4 | SbF3
SbF5 | TeF4 | IF
IF3
IF5
IF7 | XeF2
XeF4
XeF6
CsF | BaF2 | *  | HfF4 | TaF5 | WF4
WF6 | ReF4
ReF5
ReF6
ReF7 | OsF4
OsF5
OsF6 | IrF3
IrF5
IrF6 | PtF4
PtF6 | AuF3
Au2F10
AuF5·F2
| HgF2
Hg2F2 | TlF
TlF3 | PbF2
PbF4 | BiF3
BiF5 | Po | At | RnF2
Fr | Ra | **  | Rf | Db | Sg | Bh | Hs | Mt | Ds | Rg | Cn | Nh | Fl | Mc | Lv | Ts | Og
|  | ↓ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| * | LaF3 | CeF3 | Pr | NdF3 | PmF3 | SmF3
| Eu | Gd | Tb | DyF3 | Ho | Er | Tm | YbF3
| Lu |
| ** | AcF3 | ThF4 | Pa | UF3
UF4
UF5
UF6 | NpF3
NpF4
NpF5
NpF6
| PuF3
PuF4
PuF5
PuF6 | AmF3
AmF4 | CmF3 | Bk | Cf | Es | Fm | Md | No | Lr |

Other|

* AgBF4
* AgPF6
* Cs2AlF5
* K3AlF6
* Na3AlF6
* KAsF6
* LiAsF6
* NaAsF6
* HBF4
* KBF4
* LiBF4
* NaBF4
* RbBF4
* Ba(BF4)2
* Ni(BF4)2
* Pb(BF4)2
* Sn(BF4)2
* BaClF
* BaSiF6
* BaGeF6
* BrOF3
* BrO2F
* CBrF3
* CBr2F2
* CBr3F
* CClF3
* CCl2F2
* CCl3F
* CFN
* CF2O
* CF3I
* CHF3
* CH2F2
* CH3F
* C2Cl3F3
* C2H3F
* C6H5F
* C7H5F3
* C15F33N
* ClFO2
* CrFO4
* CrF2O2
* CsBF4
* NH4F
* FNO
* FNO2
* FNO3
* KHF2
* NaHF2
* ThOF2
* NH5F2
* (NH4)2SiF6
* F2OS
* F3OP
* PSF3
* HPF6
* HSbF6
* NH4PF6
* KPF6
* KSbF6
* LiPF6
* NaPF6
* NaSbF6
* Na2SiF6
* Na2TiF6
* Na2ZrF6
* TlPF6
* IOF3
* K2NbF7
* K2TaF7
* IO3F
* UO2F2

Chemical formulas

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