Kobalt

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Kobalt iku sawijining anasir kimiah kanthi cihna Co lan nomer atom 27. Kaya nikel, kobalt ditemokaké ing Bumi kanthi bentuké campuran, sing sumber asalé saka mètèorit wesi. sipat iku atos, kemeling, lan wernané klawu wesi.

Cobalt,  27Co
cobalt chips
General properties
Pangucapan Rungokakéi/ˈkbɒlt/[1]
Wujud hard lustrous bluish gray metal
Bobot atom standar (Ar, standard) 58.933194(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
ironcobaltnickel
Atomic number (Z) 27
Group group 9
Period period 4
Element category   transition metal
Blok d-block
Konfigurasi èlèktron [Ar] 3d7 4s2
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/cm3
when liquid (at m.p.) 8.86 g/cm3
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
Color lines in a spectral range
Miscellanea
Crystal structurehexagonal close-packed (hcp)
Hexagonal close packed crystal structure for cobalt
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 (t1/2) Decay mode Pro­duct
56Co syn 77.27 d ε 56Fe
57Co syn 271.79 d ε 57Fe
58Co syn 70.86 d ε 58Fe
59Co 100% stable
60Co syn 5.2714 y β, γ 60Ni
| references | in Wikidata

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