Sulphur hexafluoride molecule, computer model. This molecule is a colourless, odourless gas at room temperature. Sulphur hexafluoride is the most potent greenhouse gas yet to be evaluated (as of 2008). It has a global warming potential 22,200 times that of carbon dioxide over a 100 year period. Atoms are represented as spheres and are colour-coded: fluorine (green) and sulphur (yellow).