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
|
|
