Table of contents

This is an oxidation-reduction (redox) reaction:

S0 + 2 e- → S-II (reduction)

Mg0 - 2 e- → MgII (oxidation)

S is an oxidizing agent, Mg is a reducing agent.

Word equation

magnesium + mixed sulfur → magnesium sulfide

Input interpretation

Mg + S → Mgs

Magnesium mixed sulfur magnesium sulfide

Balanced equation

Balance the chemical equation algebraically:

Mg + S → Mgs

Add stoichiometric coefficients, c, to the reactants and products:


c1Mg + c2S → c3Mgs

Set the number of atoms in the reactants equal to the number of atoms in the products for Mg and S:

Mg: c1 = c3

S: c2 = c3

Since the coefficients are relative quantities and underdetermined, choose a coefficient to set arbitrarily. To keep the coefficients small, the arbitrary value is ordinarily one. For instance, set c1 = 1 and solve the system of equations for the remaining coefficients:

c1 = 1 c2=1 

c3 = 1

Substitute the coefficients into the chemical reaction to obtain the balanced equation:


Mg + S → Mgs