actinium

Definitions

  • WordNet 3.6
    • n actinium a radioactive element of the actinide series; found in uranium ores
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Webster's Revised Unabridged Dictionary
    • n Actinium (Chem) A supposed metal, said by Phipson to be contained in commercial zinc; -- so called because certain of its compounds are darkened by exposure to light.
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Century Dictionary and Cyclopedia
    • n actinium A supposed chemical element found associated with zinc. Its chemical and physical properties have not been fully investigated.
    • n actinium A radioactive substance found by Debierne to exist in the residues remaining from pitchblende after the extraction of the uranium: a new radio-element closely related in its chemical behavior to lanthanum, from which it has not as yet been found possible to separate it completely. It has not been obtained in a state of sufficient purity to give any characteristic spectrum and is identified and recognized entirely by its radioactive properties. Actinium itself has not been found to emit a radiation but undergoes disintegration with the formation of a series of radioactive products known as radioactinium, axtinium-X, actinium emanation, actinium A, actinium B, and actinium C. Of these, the first, second, third, and fifth emit alpha-rays, the fourth beta-rays, and the sixth beta- and gamma-rays (see obscure rays). These products are present in all ordinary actinium preparations. The occurrence of actinium indicates that it is a disintegration product of uranium, although its genetic relationship to ionium and radium has not yet been established. Actinium is identical with the emanium of Giesel. See emanation.
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Etymology

Webster's Revised Unabridged Dictionary
Gr. , , ray

Usage

In literature:

The actinium is present in negligibly small amounts.
"The Birth-Time of the World and Other Scientific Essays" by J. (John) Joly
In this class are now placed also the three radio-active gases, emanating respectively from radium, thorium, and actinium.
"A Brief Account of Radio-activity" by Francis Preston Venable
ACTINIUM, an element or elementary substance obtained in minute quantities in connection with the study of radioactivity.
"The New Gresham Encyclopedia. Vol. 1 Part 1" by Various
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In science:

An active source of actinium was covered with a sheet of mica and placed in a chamber.
Discovery of the thallium, lead, bismuth, and polonium isotopes
Discovery of actinium, thorium, protactinium, and uranium isotopes.
Discovery of the actinium, thorium, protactinium, and uranium isotopes
On-line alpha spectroscopy of neutron-deficient actinium isotopes” .
Discovery of the actinium, thorium, protactinium, and uranium isotopes
Debierne is generally credited with the discovery of actinium.
Discovery of the actinium, thorium, protactinium, and uranium isotopes
An additional short-lived chain collateral to the actinium (4n+3) natural radioactive family has also been partially identified.
Discovery of the actinium, thorium, protactinium, and uranium isotopes
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