actinium defined in 1939 yearactinium - Actinium;
actinium - Radio-active substance accompanying thorium extracted from pitchblend. It was discovered by Debierne in 1899, and appears to be identical with emanium afterwards discovered by Giesel. Actinium disintegrates on keeping, seven successive radio-products having been identified as formed during the process. Actinium emanation renders bodies with which it comes in contact temporarily radio-active. Actinium may be concentrated by normal chemical methods. See Radio activity.
near actinium in Knolik
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