91

Radioactive

Pa

Protactinium

231.04

Actinide
Solid

Discovery

Soddy, Frederick; Cranston, John & Hahn, Otto (1913)

Etymology

Greek

Meaning

First beam element

Electron configuration

Electron configuration

Crystal structure

Crystal structure

Tetragonal

Physical Properties

Phase

  (at 21 °C and 101.325 kPa)

Solid

Melting point

  (at 101.325 kPa)

1568.0 °C

1841.15 K

Boiling point

  (at 101.325 kPa)

4790.0 °C

5063.15 K

Density

  (at 21 °C and 101.325 kPa)

11.72 g/cm3

Electronegativity

1.50