Fluorine

Image by Greg Robson

Fluorine is one of the most exciting and aggressive chemicals you’re ever likely to meet. In its pure form, as a pale yellowish brown gas, it is highly poisonous and the most reactive of all elements. It’s so reactive it can react with even the most inert and stable of chemicals. Even in the dark in the extreme cold it will react explosively with hydrogen. Almost any substance, including metals and even water, will burn with a bright flame in fluorine gas. Even moist air can turn fluorine gas into hydrofluoric acid!

The discovery of fluorine was no easy task. In fact, many of the scientists who tried to study it ended up blinded or dead. After 74 years of effort (and horrible accidents) the scientist Henri Moissan finally isolated pure fluorine, earning him the Nobel Prize in 1906.

Since fluorine is such explosive stuff, some US space scientists in the 1960s have wondered if they could use it as a rocket propellant. They should have learnt the lesson from the people who first discovered fluorine. The experiments failed because fluorine was just too difficult to handle, and even the by-products of burning it turned out to be horribly toxic and corrosive. It may be useful, but fluorine is nasty stuff!

Despite a worrying tendency to burn things and kill people, fluorine does have many uses in the modern world when it is part of other compounds.

Flourine is found in many medical drugs like those used in general anaesthetic as well as certain corticosteroids, antifungal drugs, antidepressants and antibiotics. Some plastics such as the non-stick coatings on saucepans are made with fluorine – the chemical name for Teflon is polytetrafluoroethylene. Flourides are also often added to toothpaste to help keep teeth strong and prevent cavities – many countries (including some places in the UK) add fluorine to the water supply. It definitely works on keeping away tooth decay, but some people are worried about having such a reactive chemical in our water.

Image by Thegreenj

Until recently, chemicals called chloroflourocarbons (CFCs) were used all over the place in air conditioning, fridges and aerosols. The only reason we stopped using them is because we suddenly realised they were causing a massive hole in the protective ozone layer which surrounds the earth. This hole forms every spring over the Antarctic and allows dangerous UV rays to reach the earth. People believe that a lack of ozone might result in more skin cancer but no-one’s really sure what the full effects would be.