All commercial enrichment methods involve first gasifying the uranium with fluorine, creating the gas uranium hexafluoride.

FORBES: Energy & Genius

Six greenhouse gases are reported on: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulphur hexafluoride.

BBC: NI greenhouse gas emissions fall

Emissions of all the gases, except sulphur hexafluoride, fell in Northern Ireland in the period 1990 - 2007.

BBC: NI greenhouse gas emissions fall

This is done either with mineral oils, which present a fire hazard, or with sulphur hexafluoride, the most potent greenhouse gas.

ECONOMIST: Inside story

One of these, for chips, is tungsten hexafluoride gas, used to deposit tiny lines of metal in patterns to connect millions of transistors.

FORBES: Suddenly Sexy

The Russians perfected a far less energy-hogging method that uses centrifuges to spin the uranium hexafluoride at 50, 000rpm so that heavier u-238 separates from lighter u-235.

FORBES: Energy & Genius

This opinion was bolstered by a statement in the report (in a footnote) that feeding the centrifuge cascades with its input uranium hexafluoride was stopped on November 16.

FORBES: The New York Times Fails To Deliver Stuxnet's Creators

On a slightly smaller scale, there's the huge Siemens breaker I saw at the Bonneville Power Administration. (If you're thinking of buying one as an art object, ask your dealer for a Siemens 72.5 kV SF6 sulfur hexafluoride power circuit breaker).

NPR: Power Structures Shape Northwest Landscape