Radon

Observations of radon are recorded as far back as 1899. In separate experiments that year, Ernest Rutherford and Robert B. Owens, and Marie Curie and Pierre Currie observed a radioactive gas emitting from thorium and radium. A year later, Friedrich Ernst Dorn also saw a gas emanating inside tubes of radium. All five scientists were observing radon!

Rutherford went on to investigate the new gas and condensed it to a liquid in 1900. Finally, in 1908, William Ramsay and Robert Whytlaw-Gray at University College, London, gathered enough radon to learn more about it and even discovered that it was the heaviest gas known.

Radon is colorless, odorless, chemically nonreactive, and radioactive. Radon is gaseous when it decays, and therefore dangerous if inhaled. It is considered a contaminant and constantly monitored in air quality measurements.

When radon is cooled below freezing, it changes colors from yellow to orange red the more the temperature is lowered.

Once thought to cure various maladies, radon’s ionizing radiation is now known to cause cell damage, potentially leading to cancer. Still, some hospitals tried to use radon’s radiation to treat tumors directly by sealing the gas in small tubes and implanting the tubes into the tumors. These methods have been replaced with safer options. But some evidence suggests that radon can help improve some autoimmune diseases, like arthritis.

Meteorologists can also use measurements of outdoor radon to track air masses and gather information about moving weather systems.

Radon is expensive and very radioactive, so it is not used in many experiments. Not much is known about its chemical compounds, but there are a few reports of compounds made with fluorides or oxides.

Radon has 39 unstable isotopes. Radon-222 is the most common and the most stable with a half-life of only 3.8 days!

Radon is found naturally in rocks, uranium ores, phosphate rock, shales, igneous and metamorphic rocks and in some common rocks like limestone. This radon comes from the radioactive decay of radium-226. We can also detect a small amount in Earth’s atmosphere and a larger amount in areas where mining takes place.

Because radon is naturally produced in rocks, some can enter homes in the areas where the building touches soil. Scientists estimate that one gram of radon is in every square mile of soil! Radon is also industrially produced by processing uriniferous ores.