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Chromium

24
Cr
51.996
Chromium
 General | States | Energies | Oxidation & Electrons | Appearance & Characteristics | Reactions | Other Forms Radius | Conductivity | Abundance

General:

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

States:

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

Energies:

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

Appearance & Characteristics:

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

Reactions:

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:

Other Forms:

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

Radius:

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

Conductivity:

thermal conductivity: 93.9 J/m-sec-deg
electrical conductivity: 77.519 1/mohm-cm polarizability: 11.6 A^3

Abundance:

source: Chromite (oxide)
rel. abund. solar system: 4.130 log abundance earth's crust: 2 log
cost, pure: 10 $/100g cost, bulk: $/100g