thorium: Quick Facts

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Oct. 18, 2026

Facts

Also Known As	Th

Photos

A periodic table element box for thorium shows atomic number 90, symbol Th, atomic weight 232.0377, electron configuration [Rn]6d2 7s2, and the name thorium. It highlights thorium as an actinoid element, solid at room temperature, with a face-centered cubic crystal structure and weakly basic acid-base properties.

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Topics

thorium-229 radiothorium ionium thorium-232 thorium series excess thorium-230 nuclear reactor thorium processing chemical element actinoid element hydrogen carbon sodium nitrogen sulfur phosphorus boron iodine fluorine zinc

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Key People

Jöns Jacob Berzelius

Jöns Jacob Berzelius

Swedish chemist

Periodic Table of the elements concept image (chemistry)

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