Inorganic Synthesis

Pyrophoric iron


Pyrophoric iron consists of extremly small particles of elemental iron which when exposed to air oxidize so quickly that the heat of the reaction makes it glow and spark. It is caused by huge surface area these particles have. Pyrophoric iron can be easily made by thermal decomposition of iron(II) Oxalate described by following equations:

FeC2O4(s) → Fe(s) + 2CO2(g)
FeC2O4(s) → FeO(s) + CO(g) + CO2(g)

These reactions yield finely grained iron and iron(II) oxide which both are pyrophoric. When the pyrophoric iron and iron(II) oxide is exposed to air it burns as written below:

4Fe(s) + 3O2(g) → 2Fe2O3(s)
4FeO(s) + O2(g) → 2Fe2O3(s)

Needed equipment:

  • Test tube or ceramic crucible
  • Pliers
  • Ceramic cobble stone or other nonflammable surface

Needed chemicals:

Iron oxalate (7g, 38,91mmol) was poured into the test tube and heated with burner. Fe(ox).2H2O was decomposed to pyrophoric Fe and FeO, CO2 and CO.  Theoretic yield: 2,173g