General Description
A colorless odorless gas. Noncombustible. Shipped as a liquefied gas under own vapor pressure. Contact may cause frostbite. Under prolonged exposure to fire or heat the containers may rupture violently and rocket.
Reactivity Profile
This substance undergoes chemical reactions only under relatively severe circumstances. They are resistant to ignition, although they may become flammable at very high temperatures. They may be resistant to oxidation reduction, except in the most severe conditions. These materials may be nontoxic. They can asphyxiate. Contact of very cold liquefied gas with water may result in vigorous or violent boiling of the product and extremely rapid vaporization due to the large temperature differences involved. If the water is hot, there is the possibility that a liquid "superheat" explosion may occur. Pressures may build to dangerous levels if liquid gas contacts water in a closed container [Handling Chemicals Safely 1980].
Health Hazard
Vapors may cause dizziness or asphyxiation without warning. Vapors from liquefied gas are initially heavier than air and spread along ground. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire may produce irritating, corrosive and/or toxic gases.
Potential Exposure
May contain highly toxic sulfur pentafluoride as an impurity. SF6 is used in various electric power applications as a gaseous dielectric or insulator. The most extensive use is in high-voltage transformers. SF6 is also used in waveguides, linear particle accelerators; Van de Graaff generators; chemically pumped continuous-wave lasers; transmission lines; and power distribution substations. Nonelectrical applications include use as a protective atmosphere for casting of magnesium alloys and use as a leak detector or in tracing moving air masses. Several sources note that vitreous substitution of SF6 in owl monkeys results in a greater ocular vascular permeability than that caused by saline. This implies that SF6 could have an important use in retinal surgery.
Fire Hazard
Some may burn but none ignite readily. Containers may explode when heated. Ruptured cylinders may rocket.
First aid
Eye: If eye tissue is frozen, seek medical attention immediately; if tissue is not frozen, immediately and thoroughly flush the eyes with large amounts of water for at least 15 minutes, occasionally lifting the lower and upper eyelids. If irritation, pain, swelling, lacrimation, or photophobia persist, get medical attention as soon as possible. Skin: If frostbite has occurred, seek medical attention immediately; do NOT rub the affected areas or flush them with water. In order to prevent further tissue damage, do NOT attempt to remove frozen clothing from frostbitten areas. If frostbite has NOT occurred, immediately and thoroughly wash contaminated skin with soap and water. Breathing: If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform mouth-to-mouth resuscitation. Keep the affected person warm and at rest. Get medical attention as soon as possible.
Shipping
UN1080 Sulfur hexafluoride, Hazard Class: 2.2; Labels: 2.2-Nonflammable compressed gas. Cylinders must be transported in a secure upright position, in a wellventilated 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
May contain impurities that cause it to hydrolyze on contact with water, forming corrosive and toxic hydrogen fluoride. Vigorous reaction with disilane.
Description
Sulfur hexafluoride is a colorless, odorless,
nontoxic, nonflammable gas that has a high dielectric strength and serves widely as an insulating gas in electrical equipment. At atmospheric pressures it sublimes directly from the
solid to the gas phase and does not have a stable
liquid phase unless under a pressure of more
than 32 psia (221 kPa, abs). It is shipped as a
liquefied compressed gas at its vapor pressure
of 298 psig at 70°F (2050 kPa at 21.1°C).
One of the most chemically inert gases
known, it is completely stable in the presence of
most materials to temperatures of about 400°F
(204°C) and has shown no breakdown or reaction in quartz at 900°F (482°C). Sulfur hexafluoride is slightly soluble in water and oil. No
change in pH occurs when distilled water is
saturated with sulfur hexafluoride.
Waste Disposal
Return refillable compressed gas cylinders to supplier. Seal unused cylinders and return to suppliers.
Physical properties
Colorless, odorless gas; density 6.41 g/L; about five times heavier than air; liquefies at -50.7°C (triple point); density of liquid 1.88 g/mL at -50.7°C; sublimes at -63.8°C; critical temperature 45.54°C; critical pressure 37.13 atm; critical volume 199 cm3/mol; slightly soluble in water; soluble in ethanol.
Definition
ChEBI: Sulfur hexafluoride is a sulfur coordination entity consisting of six fluorine atoms attached to a central sulfur atom. It is the most potent greenhouse gas currently known, with a global warming potential of 23,900 times that of CO2 over a 100 year period (SF6 has an estimated lifetime in the atmosphere of between 800 and 3,000 years). It has a role as an ultrasound contrast agent and a member of greenhouse gas.
Preparation
Sulfur hexachloride may be prepared by reacting fluorine with sulfur or sulfur dioxide.
Brand name
SonoVue (for the microbubble formulation) (Ausimont).
Flammability and Explosibility
Nonflammable(100%)
Materials Uses
Sulfur hexafluoride is noncorrosive to all metals. It may be partially decomposed if subjected
to an electrical discharge. Some of the breakdown products are corrosive; this corrosion is
enhanced by the presence of moisture or at high
temperature. Sulfur hexafluoride decomposes
very slightly in the presence of certain metals at
temperatures in excess of 400°F (204°C); this
effect is most pronounced with silicon and carbon steels. Such breakdown, presumably catalyzed by the metals, is only several tenths of 1
percent over 1 year. Decomposition at elevated
temperatures does not occur with aluminum,
copper, brass, and silver.
Most common gasket materials, including
Teflon, neoprene, and natural rubber are suitable for sulfur hexafluoride service.
storage
All ofthe precautions necessary for the handling
of any nonflammable gas must be taken.
