Ang kromyo o cromo (Iningles chromium ) mao ang elementong kimiko sa talaang peryodiko nga may simbolo nga Cr ug kaiphan nga atomik 24. Ang kromyo mao ang puthaw nga transisyon .
Quick Facts Chromium, Panagway ...
Chromium
24
Panagway
silvery metallic
Kinatibuk-ang mga kinaiya
Ngalan, simbolo , kaiphan
chromium, Cr, 24
Paglitok
[[Help:Pronunciation respelling key|Plantilya:Smallcaps all
Kategoriyang elemento puthaw nga transisyon
Group , period , block 6 , 4 , d
Gibug-aton sa atomo 51.9961(6)
Kontorno sa elektron [ Ar ] 3d5 4s1 Electron shells of chromium (2, 8, 13, 1)
History
Pagkadiskobre Louis Nicolas Vauquelin (1797)
First isolation
Louis Nicolas Vauquelin (1798)
Physical properties
Phase magahi
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
Molar heat capacity 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
Oxidation states 6 , 5, 4, 3 , 2, 1, -1, -2acidic oxide)
Electronegativity 1.66 (Pauling scale)
Ionization energies more )1st: 652.9 kJ·mol−1
2nd: 1590.6 kJ·mol−1
3rd: 2987 kJ·mol−1
Atomic radius 128 pm
Covalent radius 139±5 pm
Miscellanea
Crystal structure body-centered cubic
Magnetic ordering AFM (rather: SDW [ 1]
Electrical resistivity (20 °C) 125 nΩ·m
Thermal conductivity 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−1
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
50 Cr4.345%
>1.3× 1018 y β+ β+ 1.167
50 Ti
51 Crsyn 27.7025 d ε -
51 V
γ 0.320
52 Cr83.789%
52 Cr is stable with 28 neutrons
53 Cr9.501%
53 Cr is stable with 29 neutrons
54 Cr2.365%
54 Cr is stable with 30 neutrons
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