Properties of Actinium (Ac)
Actinium is a chemical element with the symbol (Ac) and atomic number 89. It is a silvery-white, radioactive metal that is a part of the actinide series. Actinium was discovered in 1899 by the German chemist Friedrich Oskar Hahn and independently by the German chemist Friedrich Oskar Hahn.
The following table provides a comprehensive list of actinium (Ac) 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 | Face-centered cubic (fcc) |
| Atomic Number | 89 |
| Molar Mass | 227 g/mol |
| Density | 10060 kg/m3 |
| Mechanical Properties | Metric |
| Young’s Modulus (E) | 25 GPa |
| Thermal Properties | Metric |
| Melting Point | 1050 °C |
| Boiling Point | 3197 °C |
| Thermal Conductivity (25°C) | 12 W/m·K |
| Specific Heat Capacity (Cp) (25°C) | 120 J/kg·K |
| Coefficient of Thermal Expansion (αL) | 1.49×10-5 1/°C |
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.