thoronn.
/ˈθɔːrɒn/ Chemistry and Physics.
A radioactive isotope of radon, atomic weight 220, that is a gaseous decay product of thorium, being formed by the decay of radium 224; thorium emanation.
ΘΚΠ
the world > matter > physics > atomic nucleus > radioactive isotope > specific isotopes > [noun] > radium > radon
radium emanation1901
thoron1918
1918 Jrnl. Chem. Soc. 114 ii. 306 A rational system of nomenclature for the radioactive elements and their degradation products is suggested. Radium emanation is given the name Radon, Ro... The other emanations become Thoron, To, and Acton, Ao.
1920 E. Q. Adams in Jrnl. Amer. Chem. Soc. XLII. 2206 The names ‘radium emanation’, ‘actinium emanation’ and ‘thorium emanation’ have been shortened, respectively, to ‘radon’, ‘actinon’ and ‘thoron’, names which suggest that the element in question is an inert gas.
1938 R. W. Lawson tr. G. von Hevesy & F. A. Paneth Man. Radioactivity (ed. 2) xi. 132 The emanation of thorium (thoron) decays with a half~value period of 55 seconds.
1961 New Scientist 2 Nov. 290/3 The filter is placed in a lead cask and, after allowing four days for the decay of the ‘daughter’ products of natural radon and thoron, the total beta-activity of the sample is recorded.
1981 Indian Jrnl. Earth Sci. 8 1 (heading) On the behaviour and measurement of thoron (Rn220) in soil.
1983 Canad. Mining Jrnl. Mar. 34/1 Measurements were carried out to estimate the radon and thoron daughter levels.
This entry has not yet been fully updated (first published 1986; most recently modified version published online June 2021).
<
n.1918