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Sulfur Hexafluoride Gas makes you sound like Darth Vader

Sulfur Hexafluoride gas is one of the craziest gases we have ever gotten our hands on! This gas is five times more dense than the air we breathe which causes it to behave differently than other gases. For example, if you breathe in SF6 it will make your voice get very deep. Helium (buy it here) does the exact opposite to your voice because it is lighter than the air you normally breathe. The dense SF6 gas actually causes the speed of the sound coming from your voice box to slow down, thus giving your voice a much lower tone or timbre. Helium, on the other hand, is less dense so the sound travels faster making your voice have a higher timbre.

What is Sulfur Hexafluoride?

Sulfur Hexafluoride's name tells us what it is made of - Sulfur is the central atom and it is surrounded by six fluorine atoms (hexa- of hexafluoride is a Greek prefix meaning 6). Because of this it is often referred to by its chemical formula: SF6. It is a colorless, odorless, non-flammable gas and is 5 times more dense than air.

Is Sulfur Hexafluoride Safe to Breathe?

Yes and no. SF6 is a non-toxic gas so it does not harm the lungs of someone who breathes it but it does displace oxygen. So, when someone breathes in SF6, the dense gas sinks into the lungs and pushes oxygen out which reduces the amount of oxygen going into the person's blood stream. Breathing too much SF6 for a prolonged period could cause asphyxia.

Where can you buy Sulfur Hexafluoride?

SF6 is an industrial gas so it must be purchased from a medical, welding or industrial gas provider. We purchase ours at NORCO which is a welding and medical supplier in the United States. We would recommend calling local gas providers and seeing if they can order it for you. One reader recommended Concorde Gas as a provider of SF6. No matter where you get the gas, it is unwise to overuse SF6 as it is a potent greenhouse gas (see "Greenhouse Gas" below).

Is Sulfur Hexafluoride Expensive?

Sulfur Hexafluoride is very expensive compared to most gases that are commercially available. We have not been able to get a clear answer about why it is so expensive, but one possible explanation is that not very much SF6 is produced each year when you compare it to other more common industrial gases. The price is going to vary between locations and even time of year but to give you an idea of cost, we’ve got a Q-size Cylinder that will hold 40 pounds of SF6. The 40 pounds of SF6 costs $550 (US Dollars)!

What is Sulfur Hexafluoride Used For?

SF6 is mostly used as in high voltage electrical applications. SF6 is an effective insulator, which means it does not allow electricity to travel through the gas very easily, so it is pumped into high voltage circuit breakers and other electrical equipment to prevent arcs of electricity jumping around in the circuit and causing electrical failure.

Is Sulfur Hexafluoride a Greenhouse Gas?

Unfortunately SF6 is a powerful greenhouse gas (why does all the fun stuff have to be bad for the environment? Doesn't seem fair, does it?). As cited on Wikipedia, "According to the Intergovernmental Panel on Climate Change, SF6 is the most potent greenhouse gas that has been evaluated, with a global warming potential of 23,900 times that of CO2." Sulfur hexafluoride is also extremely long-lived, with a lifespan of 800 to 2300 years, which compounds its effectiveness as a greenhouse gas.

We took SF6 to a local CBS station to show how incredible sulfur hexafluoride gas is. Click the video above to watch.


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