radium B

American  

noun

Chemistry.

1. an isotope of lead, formed by decay of radium A, that gives rise to radium C, which is an isotope of bismuth, from which radium D, radium E, and radium F, or polonium 210, are derived.

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Etymology

Origin of radium B

First recorded in 1900–05

Example Sentences

In fact, to be brief, it is not till we come to Radium B that ß-rays of a relatively high penetrative quality are reached; and it is not till we come to Radium C that highly penetrative y-rays are obtained.

From Project Gutenberg