7783-79-1 Usage
Description
Selenium hexafluoride, also known as SeF6, is a colorless, nonflammable gas with a repulsive odor. It is highly toxic by inhalation and may decompose to emit toxic fluoride and selenium fumes when heated to high temperatures. Prolonged exposure of the container to fire or intense heat may cause selenium hexafluoride to violently rupture or rocket.
Uses
Used in Electric Industry:
Selenium hexafluoride is used as a gaseous electric insulator for its excellent insulating properties. It is commonly prepared by passing gaseous fluorine over finely divided selenium in a copper vessel.
Used in Semiconductor Industry:
Selenium hexafluoride is used in the production of arc light electrodes, electric rectifiers, and semiconductors due to its high insulation capabilities and stability.
Physical Properties:
Selenium hexafluoride is a colorless gas with a refractive index of 1.895. It has a density of 3.25 g/L at -28°C and liquefies at -34.5°C. The gas freezes at -50.8°C and sublimes at -63.8°C. It is insoluble in water.
Preparation
Selenium hexafluoride is prepared by passing fluorine gas over finely divided selenium in a copper vessel:Se + 3F2 → SeF6.
Air & Water Reactions
Insoluble in water.
Reactivity Profile
SELENIUM HEXAFLUORIDE is a colorless, poison gas, when heated to decomposition SELENIUM HEXAFLUORIDE emits very toxic fumes containing metallic selenium and selenium fluorides [Lewis, 3rd ed., 1993, p. 1131].
Safety Profile
Poison by inhalation. When heated to decomposition it emits very toxic fumes of Fand Se. See also SELENIUM COMPOUNDS and FLUORIDES.
Potential Exposure
Selenium hexafluoride, a gas, is utilized as a gaseous electric insulator.
Shipping
Selenium hexafluoride, Hazard Class: 2.3; Labels: 2.3-Poisonous gas, 8-Corrosive material Inhalation, Hazard Zone A. Cylinders must be transported in a secure upright position, in a well-ventilated truck. Protect cylinder and labels from physical damage. The owner of the compressed gas cylinder is the only entity allowed by federal law (49CFR) to transport and refill them. It is a violation of transportation regulations to refill compressed gas cylinders without the express written permission of the owner.
Incompatibilities
Hydrolyzes very slowly in cold water. Decomposes on heating, producing hydrogen fluoride, fluoride, and selenium. Contact with metal or acid will produce toxic gaseous hydrogen selenide.
Waste Disposal
Return refillable compressed gas cylinders to supplier. If possible, convert selenium compounds to an insoluble form with SO2 before landfill or solidification.
Check Digit Verification of cas no
The CAS Registry Mumber 7783-79-1 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,7,8 and 3 respectively; the second part has 2 digits, 7 and 9 respectively.
Calculate Digit Verification of CAS Registry Number 7783-79:
(6*7)+(5*7)+(4*8)+(3*3)+(2*7)+(1*9)=141
141 % 10 = 1
So 7783-79-1 is a valid CAS Registry Number.
InChI:InChI=1/F6Se/c1-7(2,3,4,5)6
7783-79-1Relevant articles and documents
Trifluoroamine oxide: Reactions with phosphorus compounds and selected elements
Gupta,Kirchmeier, Robert L.,Shreeve, Jean'ne M.
, p. 573 - 574 (2008/10/08)
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Thermochemistry of germanium monoselenide, and the Ge-Se bond dissociation enthalpy
O'Hare, P. A. G.,Susman, S.,Volin, K. J.
, p. 827 - 836 (2007/10/02)
The standard molar enthalpy of formation ΔfH0m of GeSe(cr) has been determined by fluorine-combustion calorimetry to be -(51.4 +/- 1.5) kJ * mol-1 at T = 298.15 K and p0 = 101.325 kPa.Combination of t
A fluorine-combustion calorimetric study of two molybdenum selenides: MoSe2 and Mo6Se6
O'Hare, P. A. G.,Tasker, I. R.,Tarascon, J. M.
, p. 61 - 68 (2007/10/02)
Combustion calorimetric measurements of the energies of fluorination of molybdenum selenides have yielded the following standard molar enthalpies of formation at 298.15 K and p0 = 101.325 kPa: ΔfHm0(MoSe2, cr) = -(234.2+/-3.3) kJ * mol-1 and ΔfHm0(Mo6Se6, cr) = -(477.8+/-10.0) kJ * mol-1.The dissociation enthalpy for the reaction: MoSe2(cr) = Mo(cr) + Se2(g), is (378.3+/-3.4) kJ * mol-1 at 298.15 K.A brief discussion is included of the thermodynamics of dissociation of the molybdenum dichalcogenides.
