# How can we balance one-half of an oxygen molecule, or any other diatomic, in a chemical reaction?

How can we balance oxygen or any other diatomic molecule with a fractional coefficient in a reaction? I mean, if we can balance oxygen atoms in an odd number what happens to other oxygen atom, and can this sort of reaction even happen?

• The use of fractions is irrelevant, as it's only the ratio that matters. If you don't like fractions you can multiply through by the denominator to get all whole numbers. – bon Jul 15 '15 at 15:53

Whenever a chemical reaction is written with fractional coefficients, implicitly it's meant to be interpreted as the amount of substance in moles of each species that is involved. So, it's not really one half of an oxygen molecule reacting, but 0.5 moles of $\ce{O2}$ reacting.