CAS Number54038-01-6
PubChem CIDna
Atomic Radius-
Atomic Volume-
Atomic Weight[278]
Boiling Point-
Bulk Modulus
CategoryTransition metals
Crystal Structure
Covalent Radius129
Electrical Resistivity
Electron Configuration[Rn] 5f14 6d7 7s2
Electrons per shell2, 8, 18, 32, 32, 15, 2
Heat of Fusionna
Heat of Vaporizationna
Ionization Potential-
Magnetic Ordering
Magnetic Susceptibility
Mass Number109
Melting Point-
Atomic Number268
Oxidation States3, 4, 6
Poisson Ratio
Shear Modulus
Specific Heat Capacity-
Thermal Conductivity-
Van der Waals radius
Young's Modulus
Abundance in Earth's crustna
Abundance in Universena
Mt Meitnerium 109 (278) 9 7 d 109 [Rn] 5f14 6d7 7s2 2 8 18 32 32 15 2 None Unknown 1 30 m 43.3m AlphaEmission TransitionMetal, Metal, Radioactive, Synthetic MITE-ner-i-um Synthetic radioactive metal. It has no significant commercial applications. Obtained by bombarding bismuth-209 with iron-58. N8VR7Qscq4k Meitnerium
In 1900, William Crookes isolated protactinium as an intensely radioactive material from uranium

Protactinium was first identified in 1913 by Kasimir Fajans and Oswald Helmuth Göhring in Germany.

A more stable isotope of protactinium was discovered in 1917 by Otto Hahn and Lise Meitner at the Kaiser Wilhelm Institute in Berlin. From the Greek protos meaning first 109 1982 Peter Armbruster, Gottfried Münzenber and their co-workers. Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany. Named after Lise "Meitner", the Austrian physicist

Isotopes of Protactinium

Standard Atomic Weight

Stable Isotopes

Unstable Isotopes

265Mt 266Mt 267Mt 268Mt 269Mt 270Mt 271Mt 272Mt 273Mt 274Mt 275Mt 276Mt 277Mt 278Mt 279Mt

Protactinium is toxic and highly radioactive
Protactinium is one of the rarest and most expensive naturally occurring elements
Owing to its scarcity, high radioactivity and high toxicity, there are currently no uses for protactinium outside of scientific research.

With the advent of highly sensitive mass spectrometers, an application of 231Pa as a tracer in geology and paleoceanography has become possible.

Protactinium-231 combined with the thorium-230 can be used to date marine sediments.