"Fiery rain" experiment

How to obtain the pyrophoric iron

In this sim­ple ex­per­i­ment you will see that de­pend­ing on the size of par­ti­cles, you can even set fire to iron!

Reagents and equip­ment:

  • iron(II) ox­alate di­hy­drate;
  • test tube;
  • gas burn­er;
  • test tube hold­er;
  • cot­ton wool;
  • ace­tone.

Step-by-step in­struc­tions

Heat the iron (II) ox­alate di­hy­drate in the flame of the burn­er un­til its col­or changes from yel­low to black. Sprin­kle the con­tents of the test tube on cot­ton wool soaked in ace­tone.

Pro­cess­es de­scrip­tion

Py­rophoric­i­ty is the abil­i­ty of a sol­id ma­te­ri­al to self-ig­nite in a pow­dery state. The pow­ders of sev­er­al met­als have these prop­er­ties, for ex­am­ple. When iron(II) ox­alate di­hy­drate is heat­ed, iron, car­bon diox­ide and wa­ter are re­leased in the break­down re­ac­tion. And the iron that is re­leased has py­rophoric­i­ty.

FeC₂O₄ · 2H₂O = Fe + 2CO₂ + 2H₂O

As soon as the iron par­ti­cles come into con­tact with the oxy­gen in the air, they burn, form­ing iron ox­ides.

10Fe + 7O₂ = 2Fe₂O₃ + 2Fe₃O₄

Py­rophoric­i­ty is a se­ri­ous prob­lem in in­dus­try, where fine pow­ders are used.

Safe­ty pre­cau­tions

Wear pro­tec­tive glass­es. Ob­serve safe­ty rules in work­ing with fire and flammable items and sub­stances.​

Warn­ing! Only un­der pro­fes­sion­al su­per­vi­sion.