Kobalt iku sawijining anasir kimiah kanthi cihna Co lan nomer atom 27. Kaya nikel, kobalt ditemokake ing Bumi kanthi bentuke campuran, sing sumber asale saka meteorit wesi. sipat iku atos, kemeling, lan wernane klawu wesi.

Cobalt,   ₂₇ Co

General properties
Pangucapan	i / ? k o? b ? l t / [1]
Wujud	hard lustrous bluish gray metal
Bobot atom standar ( A r, standard )	7001589331940000000♠ 58.933 194 (4) [2]
Cobalt in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson ? ↑ Co ↓ Rh iron ← cobalt → nickel
Atomic number ( Z )	27
Group	group 9
Period	period 4
Element category	transition metal
Blok	d-block
Konfigurasi elektron	[ Ar ] 3d 7 4s 2
Electrons per shell	2, 8, 15, 2
Sipat angga
Phase at  STP	solid
Melting point	1768  K ​(1495 °C, ​2723 °F)
Boiling point	3200 K ​(2927 °C, ​5301 °F)
Density (near  r.t. )	8.90 g/cm 3
when liquid (at  m.p. )	8.86 g/cm 3
Heat of fusion	16.06  kJ/mol
Heat of vaporization	377 kJ/mol
Molar heat capacity	24.81 J/(mol·K)
Vapor pressure P   (Pa) 1 10 100 1 k 10 k 100 k at  T   (K) 1790 1960 2165 2423 2755 3198
Atomic properties
Oxidation states	?3, ?1, +1, +2 , +3 , +4, +5 [3] ​(an amphoteric oxide)
Electronegativity	Pauling scale: 1.88
Ionization energies	1st: 760.4 kJ/mol 2nd: 1648 kJ/mol 3rd: 3232 kJ/mol ( more )
Atomic radius	empirical: 125  pm
Covalent radius	Low spin: 126±3 pm High spin: 150±7 pm
Spectral lines
Miscellanea
Crystal structure	​ hexagonal close-packed (hcp)
Speed of sound thin rod	4720 m/s (at 20 °C)
Thermal expansion	13.0 μm/(m·K) (at 25 °C)
Thermal conductivity	100 W/(m·K)
Electrical resistivity	62.4 nΩ·m (at 20 °C)
Magnetic ordering	ferromagnetic
Young's modulus	209 GPa
Shear modulus	75 GPa
Bulk modulus	180 GPa
Poisson ratio	0.31
Mohs hardness	5.0
Vickers hardness	1043 MPa
Brinell hardness	470?3000 MPa
CAS Number	7440-48-4
History
Discovery and first isolation	Georg Brandt (1735)
Main isotopes of cobalt
Iso­tope Abun­dance Half-life ( t 1/2 ) Decay mode Pro­duct 56 Co syn 77.27 d ε 56 Fe 57 Co syn 271.79 d ε 57 Fe 58 Co syn 70.86 d ε 58 Fe 59 Co 100% stable 60 Co syn 5.2714 y β ? , γ 60 Ni
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Rujukan [ besut | besut sumber ]

1. ↑ Oxford English Dictionary , 2nd Edition 1989.
2. ↑ Meija, J.; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)" . Pure and Applied Chemistry . 88 (3): 265?91. doi : 10.1515/pac-2015-0305 .
3. ↑ Cithakan:Greenwood&Earnshaw2nd