radium emanation

The element yields spontaneously radium emanation without any apparent diminution of its own mass.

Niton, or radium emanation, is one of the products of the disintegration of radium.

Mix very slowly and quietly in order not to release too much of the radium emanation.

Contact with radium emanation results in a deposit of the fatal radium-D, which in 40 years is but half removed.

The radium emanation is a gas about 111 times heavier than hydrogen; to this gas Sir William Ramsay has given the name niton.