NICKEL

TRANSITION ELEMENT: NICKEL GROUP

Atomic number:	28
Group numbers:	10
Period:	4
Electronic configuration:	[Ar] 3d⁸ 4s²
Formal oxidation number:	+2 +3
Electronegativities:	1.91
Atomic radius / pm:	124.6
Relative atomic mass:	58.6934(4)

Nickel was discovered by Axel Fredrik Cronstedt (SE) in 1751. The origin of the name comes from the German word kupfernickel meaning Devil's copper or St Nicholas's (Old Nick's) copper. It is a hard, malleable, silvery-white metal. Nickel is soluble in acids, resist alkalis. It can be polished to a lustrous finish. It resists corrosion in air under normal conditions. Nickel is chiefly found in pentlandite [(Ni,Fe)9S8] ore. The metal is produced by heating the ore in a blast furnace which replaces the sulfur with oxygen. The oxides are then treated with an acid that reacts with the iron not the nickel. Nickel is used in electroplating and metal alloys because of its resistance to corrosion, in nickel-cadmium batteries, and as a catalyst and for coins. The price of 99.99 % pure nickel pieces is 96.60 € for 500 g.

PHYSICAL PROPERTIES
Density / g dm^-3:	8902	(298 K)
	7780	(m.p.)
Molar volume / cm³mol^-1:	6.59	(298 K)
	7.54	(m.p.)
Electrical resistivity / µΩcm:	6.84	(20 °C)

THERMAL PROPERTIES
Thermal conductivity / W m^-1K^-1:	90.7
Melting point / °C:	1455
Boiling point / °C:	2913
Heat of fusion / kJ mol^-1:	17.6
Heat of vaporization / kJ mol^-1:	374.8
Heat of atomization / kJ mol^-1:	427.659

IONIZATION ENERGIES
First ionization energy / kJ mol^-1:	737.13
Second ionization energy / kJ mol^-1:	1753.04
Third ionization energy / kJ mol^-1:	3395.34

ABUNDANCE OF ELEMENT
in the atmosphere / ppm:	-
in the Earth's crust / ppm:	105
in the oceans / ppm:	0.0005

CRYSTALLOGRAPHIC DATA
Crystal structure:	face-centered cubic
Unit-cell dimensions / pm:	a=352.38
Space group:	Fm3m

ISOTOPES
Isotope	Relative atomic mass	Mass percent (%)
⁵⁸Ni	57.935348(2)	68.077(9)
⁶⁰Ni	59.930791(2)	26.223(8)
⁶¹Ni	60.931060(2)	1.140(1)
⁶²Ni	61.928349(2)	3.634(2)
⁶⁴Ni	63.927970(2)	0.926(1)

REDUCTION POTENTIALS
Balanced half-reaction	E^o / V
Ni²⁺ + 2e^- → Ni(s)	- 0.250
NiO₂(s) + 4H⁺ + 2e^- → Ni²⁺ + 2H₂O	+1.593
NiO₂(s) + 2H₂O + 2e^- → Ni(OH)₂(s) + 2OH^-	+0.49
Ni₂O₃(s) + 6H⁺ + 2e^- → 2Ni²⁺ + 3H₂O	+1.753
Ni₃O₄(s) + 2H₂O + 2e^- → 3HNiO₂^- + H⁺	- 0.718
Ni₃O₄(s) + 8H⁺ + 2e^- → 3Ni²⁺ + 4H₂O	+1.977
HNiO₂^- + 3H⁺ + 2e^- → Ni(s) + 2H₂O	+0.648
Ni(CN)₄^2- + e^- → Ni(CN)₃^- + CN^-	- 0.4
NiO₄^2- + 8H⁺ + 4e^- → Ni²⁺ + 4H₂O	+1.8
Ni(NH₃)₆²⁺ + 2e^- → Ni(s) + 6NH₃	- 0.49
NiS(s) (alpha) + 2e^- → Ni(s) + S^2-	+0.76
NiS(s) (gamma) + 2e^- → Ni(s) + S^2-	- 0.99