In 1871, Dmitri Mendeleev predicted the existence of an element between thorium and uranium. The actinide series was unknown at the time, so Mendeleev positioned See more

Protactinium is one of the rarest and most expensive naturally occurring elements. It is found in the form of two isotopes – Pa and Pa, with the isotope Pa occurring in two different energy … See more

Protactinium is an actinide positioned in the periodic table to the left of uranium and to the right of thorium, and many of its physical properties are intermediate between its … See more

Although protactinium is situated in the periodic table between uranium and thorium, both of which have numerous applications, there … See more

Twenty-nine radioisotopes of protactinium have been discovered. The most stable are Pa with a half-life of 32,760 years, Pa with a half-life of 27 days, and Pa with a half-life of 17.4 days. All other isotopes have half-lives shorter than 1.6 days, and the majority of … See more

Before the advent of nuclear reactors, protactinium was separated for scientific experiments from uranium ores. Since reactors have become more common, it is mostly produced as an intermediate product of nuclear fission in thorium high-temperature … See more

Here, a, b, and c are lattice constants in picometers, No is the space group number, and Z is the number of formula units See more