Triads of Iron

Characteristics:

Element Symbol Atomic number Valence electron configuration
Iron Fe 26 4s2 3d6
Cobalt Co 27 4s2 3d7
Nickel Ni 28 4s2 3d8
  • are found in fourth period

Occurence:

- are found only in their compounds

  • Fe: magnetite = Fe3o4, hematite = Fe2O3, limanite = Fe2O3 . nH2O, siderite = FeCO3 and pyrite = FeS2
  • Co: cobaltite = CoAsS
  • Ni: as component of sulphide ores or part of meteorites (alloys of Ni and Fe)

Chemical and physical properite:

- Fe:

  • a silvery-white, lustrous, malleable, ductile, magnetic, magnetizable = ferromagnetic properties, metallic element
  • in contact with oxygen it undergoes corrosion
  • base metals > is able to displace molecules of hydrogen in dilute acids

- Co + Ni:

  • good conductors
  • have ferromagnetic properties but notas good as iron

- typical oxidation numbers: +2, +3

- usually form covalent bonding

- soluble in some dilute acids (sulphuric acid, nitric acid)

Preparation:

IRON:

  • its manufacturing is don in the blast furnace > the temperature in lower part of it is about 1 700 °C and in upper part about 400 °C
  • source material for iron making: iron ores (with oxygen), carbon - reducong agent, lime stone rock = CaCO3 - slag agent > converts an assortment of rocky material of iron ore (it is not pure Fe2O3) into slag which melts and runs to the bottom
  • process description:
    • direct reduction is done by carbon
    • indirect reduction is done by CO (is formed when carbon is heated and there is not enough oxygen)
  • final product: cast iron + slag

Triads of Iron

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