Sulfur hexafluoride

 
Molecular Formula: SF₆
Molecular Weight: 146.05 g/mol
Canonical SMILES: S(F)(F)(F)(F)(F)F
InChI: InChI=1/F6S/c1-7(2,3,4,5)6
EINECS: 219-854-2
Classification Code: Diagnostic [ultrasound]
Product Categories: Inorganics; Inorganic Fluorides; Vitamin Ingredients; Chemical Synthesis; Compressed and Liquefied Gases; Synthetic Reagents
Stability: Stable. Non-flammable. Explodes on contact with disilane. Reacts with sodium.
XLogP3-AA: 4.2
H-Bond Acceptor: 6
Exact Mass: 145.96249
MonoIsotopic Mass: 145.96249
Heavy Atom Count: 7
Complexity: 62.7
Melting Point: -50 °C(lit.)
Density: 6.602 g/cm³
Boiling Point: -64 °C (lit.)
Vapor density: 5.11 (vs air)
Vapor pressure: 22 mm Hg ( 21.1 °C)
Water Solubility of Sulfur hexafluoride (CAS NO.2551-62-4): slightly

 Sulfur hexafluoride (CAS NO.2551-62-4) is used in the electrical industry as a gaseous dielectric medium for high-voltage (35 kV and above) circuit breakers, switchgear, and other electrical equipment, often replacing oil filled circuit breakers (OCBs) that can contain harmful PCBs and used in the semiconductor industry as an etchant. Sulfur hexafluoride is also used as a reagent for creating thrust in a closed Rankine cycle propulsion system, reacting with solid lithium as used in the United States Navy's Mark 50 torpedo and used as an alternative to oil in insulating high voltage equipment such as power transformers and switchgear and used to pressurize the waveguide in radar systems. The magnesium industry uses large amounts of SF6 as inert gas to fill casting forms.

 SF₆ can be prepared from the elements through exposure of S₈ to F₂. This is also the method used by the discoverers Henri Moissan and Paul Lebeau in 1901. Some other sulfur fluorides are cogenerated, but these are removed by heating the mixture to disproportionate any S₂F₁₀ (which is highly toxic, unlike SF₆) and then scrubbing the product with NaOH to destroy remaining SF₄. There is virtually no reaction chemistry for SF₆. It does not react with molten sodium, but reacts exothermically with lithium. Starting from SF₄, one can prepare SF₅Cl, which is structurally related to SF₆. The monochloride is, however, a strong oxidant and readily hydrolyzed to sulfate.

Reported in EPA TSCA Inventory.

This material is chemically inert in the pure state and is considered to be physiologically inert as well. However, as it is ordinarily obtainable, it can contain variable quantities of the low-sulfur fluorides. Some of these are toxic, very reactive chemically, and corrosive in nature. These materials can hydrolyze on contact with water to yield hydrogen fluoride, which is highly toxic and very corrosive. In high concentrations and when pure it may act as a simple asphyxiant. Incompatible with disilane. Vigorous reaction with disilane. May explode. When heated to decomposition emits highly toxic fumes of F⁻ and SO_x.
Hazard Codes: Xi
Risk Statements: 37 
R37: Irritating to respiratory system
Safety Statements: 38 
S38: In case of insufficient ventilation, wear suitable respiratory equipment.
RIDADR: UN 1080 2.2
Hazard Note: Irritant
HazardClass of Sulfur hexafluoride (CAS NO.2551-62-4): 2.2

OSHA PEL: TWA 1000 ppm
ACGIH TLV: TWA 1000 ppm
DFG MAK: 1000 ppm (6100 mg/m³)
DOT Classification:  2.2; Label: Nonflammable Gas

  Sulfur hexafluoride (CAS NO.2551-62-4), its Synonyms are Sulfur fluoride (SF6), (OC-6-11)- ; Sulfur fluoride, (OC-6-11)- ; Sulfur fluoride ; Hexafluorosulfur ; Hexafluorure de soufre ; SonoVue ; Sulphur hexafluoride . It is colourless odourless gas.