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


Name Chromium Symbol Cr
atomic number 24 Atomic weight 51.996
Density @ 293 K 7.19 g/cm3 Atomic volume 7.23 cm3/mol
Group Trans. Met. discovered 1798


state (s, l, g) s
melting point 2130.2 K boiling point 2963 K
Heat of fusion 16.90 kJ/mol Heat of vaporization 344.30 kJ/mol
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1st ionization energy 652.8 kJ/mole electronegativity 1.66
2nd ionization energy 1592 kJ/mole electron affinity 64.3 kJ/mole
3rd ionization energy 2987.2 kJ/mole Specific heat 0.45 J/gK
heat atomization 397 kJ/mole atoms

Oxidation & Electrons

Shells 2,8,13,1 electron configuration [Ar] 3d5 4s1
minimum oxidation number -2 maximum oxidation number 6
min. common oxidation no. 0 max. common oxidation no. 6
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Appearance & Characteristics

structure bcc: body-centered cubic color silvery-white
uses CrO2 tape, paint, steel toxicity
hardness 9 mohs characteristics hard


reaction with air none reaction with 6M HCl mild, = H2, CrCl3
reaction with 6M HCl mild, = H2, CrCl3 reaction with 15M HNO3 passivated
reaction with 6M NaOH
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Other Forms

number of isotopes 4 hydride(s) CrH
oxide(s) Cr2O3 CrO2 CrO3+non-stoich chloride(s) CrCl2 CrCl3


ionic radius (2- ion) pm ionic radius (1- ion) pm
atomic radius 128 pm ionic radius (1+ ion) pm
ionic radius (2+ ion) 90.5 pm ionic radius (3+ ion) 75.5 pm
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thermal conductivity 93.9 J/m-sec-deg electrical conductivity 77.519 1/mohm-cm
polarizability 11.6 A^3


source Chromite (oxide) rel. abund. solar system 4.130 log
abundance earth's crust 2 log cost, pure 10 $/100g
cost, bulk $/100g
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World Wide Web presentation of Chemicool Periodic Table is © Copyright 1996-99 by David D. Hsu. Some data were provided by and used with the permission of JCE Software and is owned and copyright by the Division of Chemical Education, Inc. Additional data were provided by Perkin-Elmer through Peter Lykos of IIT. The information may not be redistributed without the permission of David Hsu or JCE Software.