Element: Nickel

General data

Element name	Nickel
Chemical symbol	Ni
Atomic number Z	28
Year discovered	1751
Standard state (25°C)	Solid
Category	Transition metal
Block	d
Atomic mass	58.693
CPK color	#50D050

Physical properties

Melting point	1728 K (1455 °C)
Boiling point	3186 K (2913 °C)
Density	8.912 g/cm³

Energy properties

First ionization energy	7.64 eV
Electron affinity	1.156 eV

Atomic structure

Protons	28 (Atomic number)
Neutrons (Ni-58, most abundant isotope)	30
Electrons	28
Electron configuration	[Ar] 4s² 3d⁸
Oxidation states	+3, +2
Electronegativity (Pauling)	1.91
Atomic radius (van der Waals)	163 pm

Ionization energies - NIST ASD (28 states)

State	Charge	Ioniz. energy (eV)	Type
Ni I	0+	7.639878 ± 0.000017	measured
Ni II	1+	18.168838 ± 0.000025	measured
Ni III	2+	35.187 ± 0.019	measured
Ni IV	3+	54.92 ± 0.25	semi-empirical
Ni V	4+	76.06 ± 0.06	semi-empirical
Ni VI	5+	108 ± 1	semi-empirical
Ni VII	6+	132 ± 2	calculated
Ni VIII	7+	162 ± 2.1	calculated
Ni IX	8+	193.2 ± 0.5	semi-empirical
Ni X	9+	224.7 ± 0.5	semi-empirical
Ni XI	10+	319.5 ± 0.7	semi-empirical
Ni XII	11+	351.6 ± 0.3	semi-empirical
Ni XIII	12+	384.5 ± 0.5	semi-empirical
Ni XIV	13+	429.3 ± 0.8	semi-empirical
Ni XV	14+	462.8 ± 1.1	semi-empirical
Ni XVI	15+	495.4 ± 1.7	semi-empirical
Ni XVII	16+	571.07 ± 0.12	semi-empirical
Ni XVIII	17+	607.02 ± 0.019	semi-empirical
Ni XIX	18+	1540.1 ± 0.5	measured
Ni XX	19+	1646 ± 3	semi-empirical
Ni XXI	20+	1758 ± 4	semi-empirical
Ni XXII	21+	1880 ± 5	semi-empirical
Ni XXIII	22+	2008.1 ± 1.3	semi-empirical
Ni XXIV	23+	2130.5 ± 0.9	semi-empirical
Ni XXV	24+	2295.6 ± 2.1	semi-empirical
Ni XXVI	25+	2399.259 ± 0.007	calculated
Ni XXVII	26+	10288.8848 ± 0.001	calculated
Ni XXVIII	27+	10775.3948 ± 0.0004	calculated

Value type as given by NIST ASD: measured - from evaluated experimental data; calculated - from ab initio calculations (mostly highly ionised atoms that have not been measured; for the simplest ones, e.g. H I, the calculation is more accurate than measurement); semi-empirical - from interpolation, extrapolation or another semi-empirical method.

Photos

Photo of the element: Nickel (Ni) — © images-of-elements.com (CC BY 3.0)

Isotopes (35)

A	N	Half-life	Decay
Ni-48	20	2.1 ms	2p
Ni-49	21	7.5 ms	EC/β⁺
Ni-50	22	17.6 ms	EC/β⁺
Ni-51	23	23.8 ms	EC/β⁺
Ni-52	24	41.4 ms	EC/β⁺
Ni-53	25	55.2 ms	EC/β⁺
Ni-54	26	114.1 ms	EC/β⁺
Ni-55	27	204 ms	EC/β⁺
Ni-56	28	6.081 d	EC/β⁺
Ni-57	29	35.60 h	EC/β⁺
Ni-58	30	stable	-
Ni-59	31	81000 a	EC/β⁺
Ni-60	32	stable	-
Ni-61	33	stable	-
Ni-62	34	stable	-
Ni-63	35	100.8 a	β⁻
Ni-64	36	stable	-
Ni-65	37	2.5175 h	β⁻
Ni-66	38	54.6 h	β⁻
Ni-67	39	21 s	β⁻
Ni-68	40	29 s	β⁻
Ni-69	41	11.4 s	β⁻
Ni-70	42	6.0 s	β⁻
Ni-71	43	2.55 s	β⁻
Ni-72	44	1.57 s	β⁻
Ni-73	45	840 ms	β⁻
Ni-74	46	508 ms	β⁻
Ni-75	47	332 ms	β⁻
Ni-76	48	235 ms	β⁻
Ni-77	49	159 ms	β⁻
Ni-78	50	122 ms	β⁻
Ni-79	51	43 ms	β⁻
Ni-80	52	20 ms	β⁻
Ni-81	53	unknown	β⁻
Ni-82	54	unknown	β⁻

Data sources

PubChem Periodic Table API - Retrieved on 29 June 2026 - licence: CC0
IUPAC CIAAW - Abridged Standard Atomic Weights 2024 - Table version: 2024 - licence: Public domain
NNDC Wallet Cards 2023 - Data as of 15 October 2024 - licence: Public domain
Images of Elements - Retrieved on 29 June 2026 - licence: CC BY 3.0

More about the data sources