Chemicool

Ac

89

(227)
Actinium
General | States | Energies | Oxidation & Electrons |Appearance & Characteristics
Reactions | Other Forms |Radius | Conductivity | Abundance
Encyclopedia Britannica articles

General

Name Actinium Symbol Ac
atomic number 89 Atomic weight (227)
Density @ 293 K 10.07 g/cm3 Atomic volume 22.54 cm3/mol
Group Trans. Met. discovered 1899

States

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

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
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Appearance & Characteristics

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

Reactions

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
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Other Forms

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

Radius

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
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Conductivity

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

Abundance

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