Hexafluoroethane is an

organofluorine Organofluorine chemistry describes the chemistry of organofluorine compounds, organic compounds that contain a carbon–fluorine bond. Organofluorine compounds find diverse applications ranging from Lipophobicity, oil and hydrophobe, water repell ...

compound with the

chemical formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...

. It is a non-flammable colorless odorless gas negligibly soluble in

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

and slightly soluble in

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often ab ...

. Its structure is . It is an extremely potent and long-lived

greenhouse gas Greenhouse gases (GHGs) are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. Unlike other gases, greenhouse gases absorb the radiations that a planet emits, resulting in the greenhouse effect. T ...

. It is the

perfluorocarbon Fluorocarbons are chemical compounds with carbon-fluorine bonds. Compounds that contain many C-F bonds often have distinctive properties, e.g., enhanced stability, volatility, and hydrophobicity. Several fluorocarbons and their derivatives are ...

counterpart to the

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and Hydrophobe, hydrophobic; their odor is usually fain ...

ethane Ethane ( , ) is a naturally occurring Organic compound, organic chemical compound with chemical formula . At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is List of purification methods ...

Physical properties

Hexafluoroethane's

solid phase In the physical sciences, a phase is a region of material that is chemically uniform, physically distinct, and (often) mechanically separable. In a system consisting of ice and water in a glass jar, the ice cubes are one phase, the water is a ...

has two polymorphs. In the scientific literature, different

phase transition In physics, chemistry, and other related fields like biology, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic Sta ...

temperatures have been stated. The latest works assign it at 103 K (−170 °C). Below 103 K it has a slightly disordered structure, and over the transition point, it has a body centered cubic structure. The critical point is at 19.89 °C (293.04 K) and 30.39 bar. Table of densities: Vapor density is 4.823 (air = 1),

specific gravity Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...

at 21 °C is 4.773 (air = 1) and

specific volume In thermodynamics, the specific volume of a substance (symbol: , nu) is the quotient of the substance's volume () to its mass (): :\nu = \frac It is a mass-specific intrinsic property of the substance. It is the reciprocal of density (rho) ...

at 21 °C is 0.1748 m³/kg.

Uses

Hexafluoroethane is used as a versatile

etchant Etching is a printmaking technique in art. Etching may also refer to: * Etching (microfabrication), a process in producing microelectronics * Glass etching, a glass decoration technique * Chemical milling, or industrial etching * Photochemical ma ...

semiconductor A semiconductor is a material with electrical conductivity between that of a conductor and an insulator. Its conductivity can be modified by adding impurities (" doping") to its crystal structure. When two regions with different doping level ...

manufacturing. It can be used for selective etching of metal

silicide A silicide is a type of chemical compound that combines silicon and a usually more electropositive element. Silicon is more electropositive than carbon. In terms of their physical properties, silicides are structurally closer to borides than t ...

s and oxides versus their metal substrates and also for etching of

silicon dioxide Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundan ...

over

silicon Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid (sometimes considered a non-metal) and semiconductor. It is a membe ...

. The primary aluminium and the semiconductor manufacturing industries are the major emitters of hexafluoroethane using the Hall-Héroult process. Together with trifluoromethane it is used in

refrigerant A refrigerant is a working fluid used in the cooling, heating, or reverse cooling/heating cycles of air conditioning systems and heat pumps, where they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are ...

s R508A (61%) and R508B (54%). It is used as a

tamponade Tamponade () is the closure or blockage (as of a wound or body cavity) by or as if by a tampon, especially to stop bleeding. Tamponade is a useful method of stopping a hemorrhage. This can be achieved by applying an absorbent dressing directl ...

to assist in retinal reattachment following vitreoretinal surgery.

Environmental effects

Due to the high energy of C−F bonds, hexafluoroethane is nearly inert and thus acts as an extremely stable

, with an atmospheric lifetime of 10,000 years (other sources: 500 years). It has a

global warming potential Global warming potential (GWP) is a measure of how much heat a greenhouse gas traps in the atmosphere over a specific time period, relative to carbon dioxide (). It is expressed as a multiple of warming caused by the same mass of carbon dioxide ( ...

(GWP) of 9200 and an

ozone depletion potential The ozone depletion potential (ODP) of a chemical compound is the relative amount of degradation to the ozone layer it can cause, with trichlorofluoromethane (R-11 or CFC-11) being fixed at an ODP of 1.0. Chlorodifluoromethane (R-22), for examp ...

(ODP) of 0. Hexafluoroethane is included in the IPCC list of greenhouse gases. Hexafluoroethane did not exist in significant amounts in the environment prior to industrial-scale manufacturing. Atmospheric concentration of hexafluoroethane reached 3

pptv PPTV () is a Chinese video streaming website. Its predecessor, PPLive, was peer-to-peer streaming video freeware created at the Huazhong University of Science and Technology in Wuhan, Hubei Province. The group of companies that runs the webs ...

at the start of the 21st century. Its

absorption band In spectroscopy, an absorption band is a range of wavelengths, frequency, frequencies or energies in the electromagnetic spectrum that are characteristic of a particular transition from initial to final state in a substance. According to quantum ...

s in the infrared part of the spectrum cause a

radiative forcing Radiative forcing (or climate forcing) is a concept used to quantify a change to the balance of energy flowing through a planetary atmosphere. Various factors contribute to this change in energy balance, such as concentrations of greenhouse gases ...

of about 0.001 W/m².

Health risks

Due to its high

relative density Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...

, it gathers in low-lying areas, and at high concentrations it can cause

asphyxiation Asphyxia or asphyxiation is a condition of deficient supply of oxygen to the body which arises from abnormal breathing. Asphyxia causes generalized hypoxia, which affects all the tissues and organs, some more rapidly than others. There are ...

References

External links

Purification process of hexafluoroethaneProtocol for measurement of tetrafluoromethane and hexafluoroethane from primary aluminium production
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Protocol for Measurement of Tetrafluoromethane () and Hexafluoroethane () Emissions from Primary Aluminum Production
{{Authority control Perfluoroalkanes Refrigerants Greenhouse gases