SymbolNi
Latin nameNiccolum
Atomic number28
Period4
Element categoryTransition elements
Relative atomic mass58.69
GroupVIII.B
Electronegativity
1.8
Oxidation numbers
2, 3
Electron configuration
1s2 2s2 2p6 3s2 3p6 3d8 4s2
Density [g/cm3]
8.908
State
Solid
Melting point [°C]
1455
Boiling point [°C]
2732
Thermal conductivity [W m-1K-1]
90.7
Heat capacity [J K-1g-1]
0.444
Discovery
1751
Hardness [Mohs scale]
4.0
Vickers hardness [MPa]
638
Brinell hardness [MPa]
700
Young's modulus [GPa]
200
Electrical conductivity [S m-1]
1.4 · 107
Shear modulus [GPa]
76
1.st ionization energy [eV]
7.6398
2.nd ionization energy [eV]
18.168
3.rd ionization energy [eV]
35.17
Stable isotopes
5
Unstable isotopes
7