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Pronunciation: mez'o-thor'e-um

Definition: The first two disintegration products of thorium; mesothorium 1 is 228Ra, a beta emitter with a half-life of 6.7 years, decaying into mesothorium 2, which is 228Ac, a beta emitter with a half-life of 6.13 hr, which disintegrates to radiothorium (228Th).

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© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.