Chromium
24 vanadium ← chromium → manganese
-
↑
Cr
↓
Mo
Periodic table
General
Name, symbol,
number
chromium, Cr, 24
Element category
transition metal
Group, period, block 6, 4, d
Appearance
silvery metallic
Standard atomic
weight
51.9961(6) g·mol−1
Electron
configuration
[Ar] 3d5 4s1
Electrons per shell
2, 8, 13, 1 (Image)
Physical properties
Phase
solid
Density (near r.t.)
7.19 g·cm−3
Liquid density at
m.p.
6.3 g·cm−3
Melting point
2180 K
(1907 °C, 3465 °F)
Boiling point
2944 K
(2671 °C, 4840 °F)
Heat of fusion
21.0 kJ·mol−1
Heat of vaporization 339.5 kJ·mol−1
Specific heat
capacity
(25 °C) 23.35
J·mol−1·K−1
Vapor pressure
P/Pa 1
10
100 1 k
10 k 100
k
at
T/K
1656 1807 1991 2223 2530 2942
Atomic properties
Crystal structure
cubic body centered
Oxidation states
6, 5, 4, 3, 2, 1
(strongly acidic oxide)
Electronegativity
1.66 (Pauling scale)
1st: 652.9 kJ·mol−1
2nd: 1590.6 kJ·mol−1
Ionization energies
(more)
3rd: 2987 kJ·mol−1
Atomic radius
140 pm
Atomic radius (calc.)
166 pm
Covalent radius
127 pm
Miscellaneous
Magnetic ordering
AFM (rather: SDW[1])
Electrical resistivity
(20 °C) 125 nΩ·m
Thermal conductivity (300 K)
93.9 W·m−1·K−1
Thermal expansion
(25 °C) 4.9
µm·m−1·K−1
Speed of sound (thin
rod)
(20 °C) 5940 m/s
Young’s modulus
279 GPa
Shear modulus
115 GPa
Bulk modulus
160 GPa
Poisson ratio
0.21
Mohs hardness
8.5
Vickers hardness
1060 MPa
Brinell hardness
1120 MPa
CAS registry number 7440-47-3
Most stable isotopes
Main article: Isotopes of chromium
iso
NA
half-life DM DE
(MeV)
DP
50Cr 4.345% >
1.8×1017y
εε
-
50Ti
ε
-
51V
51Cr syn
27.7025 d
γ
0.320 -
52Cr 83.789% 52Cr is stable with 28
neutrons
From Wikipedia, the free encyclopedia
Chromium
1
53Cr 9.501%
53Cr is stable with 29
neutrons
54Cr 2.365%
54Cr is stable with 30
neutrons
References
Chromium (pronounced /ˈkroʊmiəm/) is a
chemical element which has the symbol Cr
and atomic number 24. It is a steely-gray,
lustrous, hard metal that takes a high polish
and has a high melting point. It is also odour-
less, tasteless, and malleable. The name of
the element is d