Properties of Protactinium (Pa)
Protactinium is a chemical element with the symbol (Pa) and atomic number 91. It is a dense, silvery-gray metal that belongs to the actinide series of elements. Protactinium is a radioactive element, and its most stable isotope, protactinium-231, has a half-life of about 32,000 years.
The following table provides a comprehensive list of protactinium (Pa) properties in both SI and US customary/Imperial units at normal temperature and pressure (NTP).
Click on the icon to switch between Metric and Imperial units.
| Physical Properties | Metric |
|---|---|
| Crystal Structure | Tetragonal |
| Atomic Number | 91 |
| Molar Mass | 231.0359 g/mol |
| Density | 15370 kg/m3 |
| Mechanical Properties | Metric |
| Young’s Modulus (E) | 76 GPa |
| Thermal Properties | Metric |
| Melting Point | 1572 °C |
| Boiling Point | 4000 °C |
| Thermal Conductivity (27°C) | 47 W/m·K |
| Coefficient of Thermal Expansion (αL) | 9.9×10-6 1/°C |
| Electrical Properties | Metric |
| Electrical Resistivity | 1.77×10-5 Ω·cm |
Unless stated otherwise, all values are taken at room temperature (approximately 20°C or 68°F) and 1 atm pressure. (1 atm = 101,325 Pa)
Related Pages
References: 1) Cardarelli, François. Materials Handbook: A Concise Desktop Reference. Switzerland: Springer International Publishing, 2018. 2) CRC Handbook of Chemistry and Physics, 97th Edition. United Kingdom: CRC Press, 2016-2017. 3) A.M. Howatson, P.G. Lun, J.D. Todd, P.D. Engineering Tables and Data. United Kingdom: University of Oxford, Department of Engineering Science, 2009.