page_title: Cobalt
section_title: Organometallic compounds
hierarchical_section_title: Cobalt / Compounds / Organometallic compounds
caption_attribution_description: Deutsch: Struktur des tetraedrischen, low-spin Cobalt(IV)-Komplexes mit 1-Norbornyl-Liganden.
context_page_description: Cobalt is a chemical element with the symbol Co and atomic number 27. Like nickel, cobalt is found in the Earth's crust only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.
  Cobalt-based blue pigments have been used since ancient times for jewelry and paints, and to impart a distinctive blue tint to glass, but the color was later thought to be due to the known metal bismuth. Miners had long used the name kobold ore for some of the blue-pigment-producing minerals; they were so named because they were poor in known metals, and gave poisonous arsenic-containing fumes when smelted. In 1735, such ores were found to be reducible to a new metal, and this was ultimately named for the kobold.
  Today, some cobalt is produced specifically from one of a number of metallic-lustered ores, such as cobaltite. The element is, however, more usually produced as a by-product of copper and nickel mining. The copper belt in the Democratic Republic of the Congo and Zambia yields most of the global cobalt production.
context_section_description: Cobaltocene is a structural analog to ferrocene, with cobalt in place of iron. Cobaltocene is much more sensitive to oxidation than ferrocene. Cobalt carbonyl (Co₂(CO)₈) is a catalyst in carbonylation and hydrosilylation reactions. Vitamin B₁₂ (see below) is an organometallic compound found in nature and is the only vitamin that contains a metal atom. An example of an alkylcobalt complex in the otherwise uncommon +4 oxidation state of cobalt is the homoleptic complex tetrakis(1-norbornyl)cobalt(IV) (Co(1-norb)₄), a transition metal-alkyl complex that is notable for its stability to β-hydrogen elimination. The cobalt(III) and cobalt(V) complexes [Li(THF)
  ₄]⁺
  [Co(1-norb)
  ₄]⁻
   and [Co(1-norb)
  ₄]⁺
  [BF
  ₄]⁻
   are also known.
caption: Structure of tetrakis(1-norbornyl)cobalt(IV)
exif: {}