Element

Protactinium Element Properties and Information

Published August 25, 2022 · Updated August 30, 2022

Protactinium Element Properties and Information

Protactinium is 91^st element on the periodic table. Elements are arranged in the periodic table on the basis of the atomic number. Atomic number is the number of protons in the nucleus of the atom. Protactinium has an atomic number of 91. It is located in the Group ‘Actinides’ and Period 7 of the periodic table of elements. It is denoted by the symbol ‘Pa’. The name is combination of ‘Protos’ which means ‘First’ and the element ‘Actinium’ which is a decay product of protactinium.

Mendeleev had predicted that there should be an element between thorium and uranium. William Crookes had separated an intensely radioactive material in 1900s but he did not analyze it. Kasimir Fajans and Otto Göhring studied protactinium in 1913 and found that it decays by mechanism of beta-emission and had a fleeting existence. Protactinium metal was obtained for the first time by Aristid von Grosse after he reduced its iodide on a heated filament. Protactinium is one of the rarest naturally occurring elements. It is also the most expensive among all elements. Protactinium occurs in most natural materials where it is homogeneously dispersed in un-extractable amounts. The ores, in which it is found, generally display concentration of 0.3-3 ppm.

Physical Properties

Protactinium is a radioactive element which belongs to the actinide series. It is dense and has a silver-grey appearance.
The atomic mass of protactinium is 231.03.
The melting point of protactinium is 1600°C.
The boiling point of protactinium is unknown.
The density of protactinium is 15370 in S.I. units at 20°C.
Protactinium crystallizes in body-centered tetragonal structure.
The properties of protactinium are intermediate of thorium and uranium.
Protactinium is paramagnetic in nature.

About 30 isotopes of protactinium have been discovered so far; protactinium-231 is the most stable among them.

Chemical Properties

Protactinium compounds generally display oxidation states of +4 and +5. This is true for solutions as well as solids.
Some solid phase protactinium compounds are observed to display oxidation states of +3 and +2.

Protactinium is observed to form oxides, hydrides, halides, and orgonametallic compounds.

Methods of Production

Nuclear Fission: The thorium-230 is radiated with slow neutrons to yield protactinium-231. Another way to obtain protactinium is by irradiating thorium-232 with fast neutrons.

Relevance in Chemical or Related Industries

Protactinium has no industrial applications.

Relevance in Other Industries

Tracing: Modern mass spectrometers can measure of ratio of protactinium-231 to thorium-230; thus, radiometric dating of sediments can be done upto 175000 years.

Modeling: of formation of minerals and melting of ice age glaciers.

Health Effects on Exposure

Inhalation or Ingestion: Protactinium poses serious problem when it enters the body. The major problem which it can cause is cancer. The movement of protactinium within the body is capable of upsetting almost all organs.