Cleveite is an impure

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is conside ...

variety of uraninite containing

uranium Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...

, found in

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...

. It has the composition UO₂ with about 10% of the uranium substituted by rare-earth elements. It was named after Swedish chemist

Per Teodor Cleve Per Teodor Cleve (10 February 1840 – 18 June 1905) was a Swedish chemist, biologist, mineralogist and oceanographer. He is best known for his discovery of the chemical elements holmium and thulium. Born in Stockholm in 1840, Cleve earned ...

. Cleveite was the first known terrestrial source of

helium Helium (from ) is a chemical element; it has chemical symbol, symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert gas, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is ...

, which is created over time by

alpha decay Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus). The parent nucleus transforms or "decays" into a daughter product, with a mass number that is reduced by four and an a ...

of the uranium and accumulates trapped (occluded) within the mineral. The first sample of helium was obtained by William Ramsay in 1895 when he treated a sample of the mineral with

acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...

.https://archive.org/details/becquerelraysthe00raylrich Rayleigh, Robert and John Strutt, 1904, The Becquerel rays and the properties of radium, London, E. Arnold. Cleve and

Abraham Langlet Nils Abraham Langlet (9 July 1868 – 30 March 1936; known by his second given name) was a Swedish chemist. Biography Langlet was born in Södertälje, Sweden. He was the son of architect Emil Victor Langlet (1824–1898) and his wife, author Cl ...

succeeded in isolating helium from cleveite at about the same time. Yttrogummite is a variant of cleveite also found in

References

Uranium(IV) minerals Thorium minerals Oxide minerals {{oxide-mineral-stub

See also

References