Barium fluoride

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Barium fluoride
Barium fluoride crystal sample.jpg
Fluorite-unit-cell-3D-ionic.png
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.029.189 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
RTECS number
  • CQ9100000
UNII
  • InChI=1S/Ba.2FH/h;2*1H/q+2;;/p-2 Yes check.svgY
    Key: OYLGJCQECKOTOL-UHFFFAOYSA-L Yes check.svgY
  • F[Ba]F
  • [Ba+2].[F-].[F-]
Properties
BaF2
Molar mass 175.324 g/mol [1]
Appearancewhite 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]
1.58 g/L (10 °C)
1.61 g/L (25 °C) [2]
1.84·10−7 [3]
Solubility soluble in methanol, ethanol
−51·10−6 cm3/mol [4]
Thermal conductivity 10.9 W/(m·K) [5]
  • 1.557 (200 nm)
  • 1.4744 (589 nm)
  • 1.4014 (10 μm)
[6]
Structure [7]
Fluorite (cubic), cF12
Fm3m, No. 225
a = 0.62 nm
4
Thermochemistry [8]
71.2 J/(mol·K)
Std molar
entropy (S⦵298)
96.4 J/(mol·K)
−1207.1 kJ/mol
−1156.8 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Toxic
GHS labelling:
GHS-pictogram-exclam.svg
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
250 mg/kg, oral (rat)
Safety data sheet (SDS) PubChem
Related compounds
Other anions
Other cations
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Barium fluoride is an inorganic compound with the formula Ba F 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 PbCl2 structure. [10] Like CaF2, it is resilient to and insoluble in water.

Contents

Above ca. 500 °C, BaF2 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.

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 BaF2 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]

Related Research Articles

<span class="mw-page-title-main">Barium</span> Chemical element, symbol Ba and atomic number 56

Barium is a chemical element; it has symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element.

<span class="mw-page-title-main">Anthracene</span> Chemical compound

Anthracene is a solid polycyclic aromatic hydrocarbon (PAH) of formula C14H10, consisting of three fused benzene rings. It is a component of coal tar. Anthracene is used in the production of the red dye alizarin and other dyes. Anthracene is colorless but exhibits a blue (400–500 nm peak) fluorescence under ultraviolet radiation.

<span class="mw-page-title-main">Scintillator</span> Material which glows when excited by ionizing radiation

A scintillator is a material that exhibits scintillation, the property of luminescence, when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate. Sometimes, the excited state is metastable, so the relaxation back down from the excited state to lower states is delayed. The process then corresponds to one of two phenomena: delayed fluorescence or phosphorescence. The correspondence depends on the type of transition and hence the wavelength of the emitted optical photon.

Calcium fluoride is the inorganic compound of the elements calcium and fluorine with the formula CaF2. It is a white solid that is practically insoluble in water. It occurs as the mineral fluorite (also called fluorspar), which is often deeply coloured owing to impurities.

<span class="mw-page-title-main">Magnesium fluoride</span> Chemical compound of magnesium and fluorine

Magnesium fluoride is an ionically bonded inorganic compound with the formula MgF2. The compound is a white crystalline salt and is transparent over a wide range of wavelengths, with commercial uses in optics that are also used in space telescopes. It occurs naturally as the rare mineral sellaite.

<span class="mw-page-title-main">Gas laser</span> Laser in which electricity is discharged through gas

A gas laser is a laser in which an electric current is discharged through a gas to produce coherent light. The gas laser was the first continuous-light laser and the first laser to operate on the principle of converting electrical energy to a laser light output. The first gas laser, the Helium–neon laser (HeNe), was co-invented by Iranian engineer and scientist Ali Javan and American physicist William R. Bennett, Jr., in 1960. It produced a coherent light beam in the infrared region of the spectrum at 1.15 micrometres.

<span class="mw-page-title-main">Caesium fluoride</span> Chemical compound

Caesium fluoride or cesium fluoride is an inorganic compound with the formula CsF and it is a hygroscopic white salt. Caesium fluoride can be used in organic synthesis as a source of the fluoride anion. Caesium also has the highest electropositivity of all known elements and fluorine has the highest electronegativity of all known elements.

<span class="mw-page-title-main">Caesium iodide</span> Chemical compound

Caesium iodide or cesium iodide is the ionic compound of caesium and iodine. It is often used as the input phosphor of an X-ray image intensifier tube found in fluoroscopy equipment. Caesium iodide photocathodes are highly efficient at extreme ultraviolet wavelengths.

<span class="mw-page-title-main">Sodium iodide</span> Chemical compound

Sodium iodide (chemical formula NaI) is an ionic compound formed from the chemical reaction of sodium metal and iodine. Under standard conditions, it is a white, water-soluble solid comprising a 1:1 mix of sodium cations (Na+) and iodide anions (I−) in a crystal lattice. It is used mainly as a nutritional supplement and in organic chemistry. It is produced industrially as the salt formed when acidic iodides react with sodium hydroxide. It is a chaotropic salt.

<span class="mw-page-title-main">Beryllium fluoride</span> Chemical compound

Beryllium fluoride is the inorganic compound with the formula Be F2. This white solid is the principal precursor for the manufacture of beryllium metal. Its structure resembles that of quartz, but BeF2 is highly soluble in water.

<span class="mw-page-title-main">Lithium fluoride</span> Chemical compound

Lithium fluoride is an inorganic compound with the chemical formula LiF. It is a colorless solid that transitions to white with decreasing crystal size. Its structure is analogous to that of sodium chloride, but it is much less soluble in water. It is mainly used as a component of molten salts. Partly because Li and F are both light elements, and partly because F2 is highly reactive, formation of LiF from the elements releases one of the highest energies per mass of reactants, second only to that of BeO.

<span class="mw-page-title-main">Neutron detection</span>

Neutron detection is the effective detection of neutrons entering a well-positioned detector. There are two key aspects to effective neutron detection: hardware and software. Detection hardware refers to the kind of neutron detector used and to the electronics used in the detection setup. Further, the hardware setup also defines key experimental parameters, such as source-detector distance, solid angle and detector shielding. Detection software consists of analysis tools that perform tasks such as graphical analysis to measure the number and energies of neutrons striking the detector.

<span class="mw-page-title-main">Plutonium tetrafluoride</span> Chemical compound

Plutonium(IV) fluoride is a chemical compound with the formula (PuF4). This salt is generally a brown solid but can appear a variety of colors depending on the grain size, purity, moisture content, lighting, and presence of contaminants. Its primary use in the United States has been as an intermediary product in the production of plutonium metal for nuclear weapons usage.

<span class="mw-page-title-main">Strontium fluoride</span> Chemical compound

Strontium fluoride, SrF2, also called strontium difluoride and strontium(II) fluoride, is a fluoride of strontium. It is a brittle white crystalline solid. In nature, it appears as the very rare mineral strontiofluorite.

<span class="mw-page-title-main">Bismuth germanate</span> Inorganic chemical compound of bismuth, germanium and oxygen

Bismuth germanium oxide or bismuth germanate is an inorganic chemical compound of bismuth, germanium and oxygen. Most commonly the term refers to the compound with chemical formula Bi4Ge3O12 (BGO), with the cubic evlitine crystal structure, used as a scintillator. (The term may also refer to a different compound with formula Bi12GeO20, an electro-optical material with sillenite structure, and Bi2Ge3O9.)

<span class="mw-page-title-main">Beryllium chloride</span> Chemical compound

Beryllium chloride is an inorganic compound with the formula BeCl2. It is a colourless, hygroscopic solid that dissolves well in many polar solvents. Its properties are similar to those of aluminium chloride, due to beryllium's diagonal relationship with aluminium.

<span class="mw-page-title-main">Krypton</span> Chemical element, symbol Kr and atomic number 36

Krypton is a chemical element; it has symbol Kr and atomic number 36. It is a colorless, odorless, tasteless noble gas that occurs in trace amounts in the atmosphere and is often used with other rare gases in fluorescent lamps. Krypton is chemically inert.

<span class="mw-page-title-main">Barium borate</span> Chemical compound

Barium borate is an inorganic compound, a borate of barium with a chemical formula BaB2O4 or Ba(BO2)2. It is available as a hydrate or dehydrated form, as white powder or colorless crystals. The crystals exist in the high-temperature α phase and low-temperature β phase, abbreviated as BBO; both phases are birefringent, and BBO is a common nonlinear optical material.

<span class="mw-page-title-main">Fluorine azide</span> Chemical compound

Fluorine azide or triazadienyl fluoride is a yellow green gas composed of nitrogen and fluorine with formula FN3. Its properties resemble those of ClN3, BrN3, and IN3. The bond between the fluorine atom and the nitrogen is very weak, leading to this substance being very unstable and prone to explosion. Calculations show the F–N–N angle to be around 102° with a straight line of 3 nitrogen atoms.

The borate fluorides or fluoroborates are compounds containing borate or complex borate ions along with fluoride ions that form salts with cations such as metals. They are in the broader category of mixed anion compounds. They are not to be confused with tetrafluoroborates (BF4) or the fluorooxoborates which have fluorine bonded to boron.

References

  1. 1 2 3 4 5 Haynes, p. 4.49
  2. ↑ Haynes, p. 5.167
  3. ↑ John Rumble (June 18, 2018). 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. Bibcode:1974JAP....45..892H. doi:10.1063/1.1663334.
  8. ↑ Haynes, p. 5.5
  9. ↑ Radtke A.S., Brown G.E. (1974). "Frankdicksonite, BaF2, a New Mineral from Nevada" (PDF). American Mineralogist. 59: 885–888.
  10. ↑ Wells, A.F. (1984). Structural inorganic chemistry −5th Edition. Oxford: Clarendon Press. ISBN   0-19-855370-6.
  11. ↑ "Crystran Ltd. Optical Component Materials". Archived from the original on 11 June 2010. Retrieved 29 December 2009.
  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. Bibcode:1983NIMPR.206..169L. doi:10.1016/0167-5087(83)91254-1.
  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)" (PDF). The Journal of Chemical Physics. 94 (5): 3762. Bibcode:1991JChPh..94.3762S. doi:10.1063/1.459748. hdl: 10486/7315 .
  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.

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