Sulfur hexafluoride

Sulfur hexafluoride, also known as sulfur(VI) fluoride, is a chemical compound. Its chemical formula is SF6. It contains sulfur in its +6 oxidation state. It also contains fluoride ions.

BBC News says "It's the most powerful greenhouse gas known to humanity, and emissions have risen rapidly in recent years. Sulphur hexafluoride, or SF6, is widely used in the electrical industry to prevent short circuits and accidents. Leaks of the little-known gas in the UK and the rest of the EU in 2017 were the equivalent of putting an extra 1.3 million cars on the road".McGrath, Matt 2019. Climate change: Electrical industry's 'dirty secret' boosts warming. BBC News Science & Environment.

Properties
Sulfur hexafluoride is a colorless, odorless gas. It is very heavy for a gas (about 5 times heavier than air). It is non-reactive, and hard to find anything that reacts with it. It is a strong greenhouse gas. This has made people put some restrictions on using it.

Preparation
It is made by reacting sulfur with fluorine. That combination also makes toxic disulfur decafluoride, which has to be removed.

Uses
It is used in electronics and various electrical devices. It can be used in the body since it is not toxic. It can be used as a test gas to look where gas flows in a heater system, for example. It is detected easily. It is used in some torpedoes. Lithium is one of the only things that reacts with sulfur hexafluoride. Sulfur hexafluoride is sprayed on lithium. This makes the lithium very hot. It creates steam from water and shoots the torpedo. It can be breathed in to make the voice deeper. This is the opposite of breathing in helium gas.

Safety
Sulfur hexafluoride is not toxic. It can fill up in closed spaces though. A person may suffocate in the closed space if sulfur hexafluoride has pushed out the oxygen from the space.
Greenhouse gas
According to the Intergovernmental Panel on Climate Change,  is the most potent greenhouse gas that it has evaluated, with a global warming potential (GWP) of 22,800Intergovernmental Panel on Climate Change, Working Group 1, Climate Change 2007, Chapter 2.10.2. times that of  when compared over a 100-year period.  Measurements of SF6 show that its global average mixing ratio has increased by about 0.2 ppt per year to over 7 ppt.  Sulfur hexafluoride is also extremely long-lived. It is inert in the troposphere and stratosphere. It has an estimated atmospheric lifetime of 800–3200 years.  is very stable. (For countries reporting their emissions to the UNFCCC, a GWP of 23,900 for  was suggested at the third Conference of the Parties: GWP used in Kyoto protocol). Average global SF6 concentrations increased by about seven percent per year during the 1980s and 1990s, mostly as the result of its use in the magnesium production industry, and by electrical utilities and electronics manufacturers. Given the low amounts of SF6 released compared to carbon dioxide, its overall contribution to global warming is estimated to be less than 0.2 percent.

In Europe,  falls under the F-Gas directive which ban or control its use in several ways. Since 1 January 2006,  is banned as a tracer gas and in all applications except high-voltage switchgear.

Related pages
Sodium fluoride
Potassium fluoride
 References 

Category:Sulfur compounds
Category:Fluorine compounds
Category:Greenhouse gases