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


Name Barium Symbol Ba
atomic number 56 Atomic weight 137.33
Density @ 293 K 3.51 g/cm3 Atomic volume 39.24 cm3/mol
Group Alkali Earth discovered 1808


state (s, l, g) s
melting point 998.2 K boiling point 2123 K
Heat of fusion 7.750 kJ/mol Heat of vaporization 142.0 kJ/mol
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1st ionization energy 502.9 kJ/mole electronegativity 0.89
2nd ionization energy 965.2 kJ/mole electron affinity kJ/mole
3rd ionization energy kJ/mole Specific heat 0.204 J/gK
heat atomization 180 kJ/mole atoms

Oxidation & Electrons

Shells 2,8,18,18,8,2 electron configuration [Xe] 6s2
minimum oxidation number 0 maximum oxidation number 2
min. common oxidation no. 0 max. common oxidation no. 2
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Appearance & Characteristics

structure bcc: body-centered cubic color silvery-white
uses X-ray imaging agnt(BaSO4) toxicity
hardness mohs characteristics soft


reaction with air vigorous,wt/ht= BaO,Ba2N3 reaction with 6M HCl vigorous, = H2, BaCl2
reaction with 6M HCl vigorous, = H2, BaCl2 reaction with 15M HNO3 mild, = Ba(NO3)2
reaction with 6M NaOH passivated
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Other Forms

number of isotopes 7 hydride(s) BaH2
oxide(s) BaO chloride(s) BaCl2


ionic radius (2- ion) pm ionic radius (1- ion) pm
atomic radius 222 pm ionic radius (1+ ion) pm
ionic radius (2+ ion) 149 pm ionic radius (3+ ion) pm
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thermal conductivity 18.4 J/m-sec-deg electrical conductivity 1/mohm-cm
polarizability 39.7 A^3


source Barite (sulfate) rel. abund. solar system 0.652 log
abundance earth's crust 2.6 log cost, pure 55 $/100g
cost, bulk $/100g
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