Selenium hexafluoride
Encyclopedia
Selenium hexafluoride is the inorganic compound
with the formula
SeF6. It is a colourless gas described as having a "repulsive" odor. It is not widely encountered and has no commercial applications.
. The compound has octahedral molecular geometry
with Se-F bond length 168.8 pm.
SeF6 can be prepared from the elements or by the reaction of bromine trifluoride
(BrF3) with selenium dioxide
. The crude product is 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, The gas can be passed through 10% NaOH or KOH without change, but reacts with gaseous ammonia
at 200 °C.
and ACGIH standards for selenium hexafluoride exposure is an upper limit of 0.05 ppm in air averaged over an eight-hour work shift.
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
SeF6. It is a colourless gas described as having a "repulsive" odor. It is not widely encountered and has no commercial applications.
Structure, preparation, and reactions
Like many compounds of selenium, SeF6 is hypervalentHypervalent molecule
A hypervalent molecule is a molecule that contains one or more main group elements formally bearing more than eight electrons in their valence shells...
. The compound has octahedral molecular geometry
Octahedral molecular geometry
In chemistry, octahedral molecular geometry describes the shape of compounds where in six atoms or groups of atoms or ligands are symmetrically arranged around a central atom, defining the vertices of an octahedron...
with Se-F bond length 168.8 pm.
SeF6 can be prepared from the elements or by the reaction of bromine trifluoride
Bromine trifluoride
Bromine trifluoride is an interhalogen compound with the formula BrF3. This toxic, colourless, and corrosive liquid is soluble in sulfuric acid but explodes on contact with water and organic compounds. It is a powerful fluorinating agent and an ionizing inorganic solvent...
(BrF3) with selenium dioxide
Selenium dioxide
Selenium dioxide is the chemical compound with the formula SeO2. This colorless solid is one of the most frequently encountered compounds of selenium.-Properties:...
. The crude product is 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, The gas can be passed through 10% NaOH or KOH without change, but reacts with gaseous ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
at 200 °C.
Safety
Selenium hexafluoride is toxic even at low concentrations. In the U.S., OSHAOccupational Safety and Health Administration
The United States Occupational Safety and Health Administration is an agency of the United States Department of Labor. It was created by Congress of the United States under the Occupational Safety and Health Act, signed by President Richard M. Nixon, on December 29, 1970...
and ACGIH standards for selenium hexafluoride exposure is an upper limit of 0.05 ppm in air averaged over an eight-hour work shift.
External links
- ATSDR ToxFAQs - Selenium Hexafluoride U.S. Department of Health and Human Services
- WebBook page for SeF6