SHEET /m/protactinium · PubChem CID 23945 · CAS 7440-13-3 · REV 2026.07
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Protactinium
from sourcePa · 231.03588 g/mol
brevium · Pa · Element-Pa
What is Protactinium?
One of the rarest and most expensive naturally occurring elements, a radioactive metal that exists mainly as a step in uranium's decay. Element 91. from source
CategoryElement & material
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Fig. 1 · 2D structure RDKit
SMILES
[Pa]Where you'll find it
A pure element or an engineered material, rather than an ingredient in a product. See the rest of the element & material group.