ChemiPlus Logo
Dictionary - Training


 General | States | Energies | Oxidation & Electrons | Appearance & Characteristics | Reactions | Other Forms Radius | Conductivity | Abundance


Name: Actinium Symbol: Ac
Group: Trans. Met. Atomic weight: (227)
Density @ 293 K: 10.07 g/cm3 Atomic volume: 22.54 cm3/mol
Group: Trans. Met. discovered: 1899


state (s, l, g): s
melting point: 1323.2 K boiling point: 2743 K
Heat of fusion: ? Heat of vaporization: ?


1st ionization energy: 499 kJ/mole
electronegativity: 1.1 2nd ionization energy: 1170 kJ/mole
electron affinity: kJ/mole 3rd ionization energy: kJ/mole
Specific heat: ? heat atomization: 385 kJ/mole atoms

Oxidation & Electrons:

Shells: 2,8,18,32,18,9,2 electron configuration: [Rn] 6d1 7s2
minimum oxidation number: 0 maximum oxidation number: 3
min. common oxidation no.: 0 max. common oxidation no.: 3

Appearance & Characteristics:

structure: fcc: face-centered cubic color: silvery-white
uses: thermoelectric power toxicity:
hardness: mohs characteristics: Radioactive


reaction with air: mild, w/ht, =>Ac2O3
reaction with 6M HCl: mild, =>H2, AcCl3 reaction with 6M HCl: mild, =>H2, AcCl3
reaction with 15M HNO3: mild, =>Ac(NO3)3 reaction with 6M NaOH:

Other Forms:

number of isotopes: 2 hydride(s): AcH2
oxide(s): Ac2O3 chloride(s): AcCl3


ionic radius (2- ion): pm ionic radius (1- ion): pm
atomic radius: pm ionic radius (1+ ion): pm
ionic radius (2+ ion): pm ionic radius (3+ ion): 126 pm


thermal conductivity: J/m-sec-deg
electrical conductivity: 1/mohm-cm polarizability: 32.1 A^3


source: Synthetic(U-235 decay)
rel. abund. solar system: log abundance earth's crust: -9.3 log
cost, pure: $/100g cost, bulk: $/100g