Selenium Hexafluoride

Selenium hexafluoride
Names
	IUPAC name Selenium hexafluoride
	Other names Selenium(VI) fluoride, Selenium fluoride
Identifiers
CAS Number	7783-79-1 ;
3D model (JSmol)	Interactive image;
ChemSpider	22964 ;
PubChem CID	24558;
RTECS number	VS9450000;
UNII	H91D37I668 ;
	InChI InChI=1S/F6Se/c1-7(2,3,4,5)6 Key: LMDVZDMBPZVAIV-UHFFFAOYSA-N ; InChI=1S/F6Se/c1-7(2,3,4,5)6 Key: LMDVZDMBPZVAIV-UHFFFAOYAP;
	SMILES F[Se](F)(F)(F)(F)F;
Properties
Chemical formula	SeF6
Molar mass	192.9534 g/mol
Appearance	colourless gas
Density	0.007887 g/cm3
Melting point	−39 °C (−38 °F; 234 K)
Boiling point	−34.5 °C (−30.1 °F; 238.7 K) sublimes
Solubility in water	insoluble
Vapor pressure	>1 atm (20°C)
Magnetic susceptibility (χ)	−51.0·10−6 cm3/mol
Refractive index (nD)	1.895
Structure
Crystal structure	Orthorhombic, oP28
Space group	Pnma, No. 62
Coordination geometry	octahedral (Oh)
Dipole moment	0
Thermochemistry
Std enthalpy of; formation (ΔfH⦵298)	-1030 kJ/mol
Hazards
Main hazards	toxic, corrosive
NFPA 704 (fire diamond)	0 3 0
	Lethal dose or concentration (LD, LC):
LCLo (lowest published)	10 ppm (rat, 1 hr); 10 ppm (mouse, 1 hr); 10 ppm (guinea pig, 1 hr)
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 0.05 ppm (0.4 mg/m3)
REL (Recommended)	TWA 0.05 ppm
IDLH (Immediate danger)	2 ppm
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
	verify (what is ?)
	Infobox references

Selenium hexafluoride is the inorganic compound with the formula SeF₆. It is a very toxic colourless gas described as having a "repulsive" odor.^[5] It is not widely encountered and has no commercial applications.^[6]

Structure, preparation, and reactions

SeF₆ has octahedral molecular geometry with an Se−F bond length of 168.8 pm. In terms of bonding, it is hypervalent.

SeF₆ can be prepared from the elements.^[7] It also forms by the reaction of bromine trifluoride (BrF₃) with selenium dioxide. The crude product can be purified by sublimation.

The relative reactivity of the hexafluorides of S, Se, and Te follows the order TeF₆ > SeF₆ > SF₆, the latter being completely inert toward hydrolysis until high temperatures. SeF₆ also resists hydrolysis.^[3] The gas can be passed through 10% NaOH or KOH without change, but reacts with gaseous ammonia at 200 °C.^[8]

Safety

Although selenium hexafluoride is quite inert and slow to hydrolyze, it is toxic even at low concentrations,^[9] especially by longer exposure. In the U.S., OSHA and ACGIH standards for selenium hexafluoride exposure is an upper limit of 0.05 ppm in air averaged over an eight-hour work shift. Additionally, selenium hexafluoride is designated as IDLH chemical with a maximum allowed exposure limit of 2 ppm.^[10]

References

↑ Lide, D. R., ed (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
↑ ^2.0 ^2.1 ^2.2 ^2.3 NIOSH Pocket Guide to Chemical Hazards. "#0551". National Institute for Occupational Safety and Health (NIOSH). https://www.cdc.gov/niosh/npg/npgd0551.html.
↑ ^3.0 ^3.1 Wiberg, E.; Holleman, A. F. (2001). Inorganic Chemistry. Elsevier. ISBN 0-12-352651-5.
↑ "Selenium hexafluoride". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH). https://www.cdc.gov/niosh/idlh/7783791.html.
↑ "Material Safety". http://www.cpcb.nic.in/divisionsofheadoffice/pci-ssi/MATERIAL_SAFETY-DATABASE/MSDS2008/558.pdf.
↑ Langner, B. E.. "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a23_525.
↑ Yost, D. M.; Simons, J. H. (1939). "Sulfur, Selenium, and Tellurium Hexafluorides". Inorganic Syntheses. 1. pp. 121–122. doi:10.1002/9780470132326.ch44. ISBN 9780470132326.
↑ Krebs, B.; Bonmann, S.; Eidenschink, I. (1994). "Selenium-Inorganic Chemistry". in King, R. B.. Encyclopedia of Inorganic Chemistry. John Wiley & Sons. ISBN 0-471-93620-0.
↑ "Medical Management Guidelines for Selenium Hexafluoride (SeF₆)". CDC ATSDR. http://www.atsdr.cdc.gov/MMG/MMG.asp?id=1015&tid=215.
↑ Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs)

External links

ATSDR ToxFAQs - Selenium Hexafluoride U.S. Department of Health and Human Services
CDC - NIOSH Pocket Guide to Chemical Hazards U.S. Department of Health and Human Services
WebBook page for SeF₆

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Original source: https://en.wikipedia.org/wiki/Selenium hexafluoride. Read more

[CRC-1] Lide, D. R., ed (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.

[PGCH-2] 2.0 ^2.1 ^2.2 ^2.3 NIOSH Pocket Guide to Chemical Hazards. "#0551". National Institute for Occupational Safety and Health (NIOSH). https://www.cdc.gov/niosh/npg/npgd0551.html.

[Wiberg&Holleman-3] 3.0 ^3.1 Wiberg, E.; Holleman, A. F. (2001). Inorganic Chemistry. Elsevier. ISBN 0-12-352651-5.

[4] "Selenium hexafluoride". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH). https://www.cdc.gov/niosh/idlh/7783791.html.

[decompose-5] "Material Safety". http://www.cpcb.nic.in/divisionsofheadoffice/pci-ssi/MATERIAL_SAFETY-DATABASE/MSDS2008/558.pdf.

[6] Langner, B. E.. "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a23_525.

[7] Yost, D. M.; Simons, J. H. (1939). "Sulfur, Selenium, and Tellurium Hexafluorides". Inorganic Syntheses. 1. pp. 121–122. doi:10.1002/9780470132326.ch44. ISBN 9780470132326.

[Krebs-8] Krebs, B.; Bonmann, S.; Eidenschink, I. (1994). "Selenium-Inorganic Chemistry". in King, R. B.. Encyclopedia of Inorganic Chemistry. John Wiley & Sons. ISBN 0-471-93620-0.

[toxic-9] "Medical Management Guidelines for Selenium Hexafluoride (SeF₆)". CDC ATSDR. http://www.atsdr.cdc.gov/MMG/MMG.asp?id=1015&tid=215.

[10] Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs)

v t e Selenium compounds
Se(−II)	Ag₂Se Al₂Se₃ CaSe Se²⁻
Se(0,I)	Se₃S₅
Se(I)	Se₂S₆ Se₂Cl₂ C₃H₇NO₂Se
Se(II)	SeS₂
Se(IV)	SeCl₄ SeF₄ SeO₂ SeS₂ SeOBr₂ SeOCl₂
Se(VI)	SeF₆ SeO₃ SeO₂F₂