Thermite is the mixture of Fe2O3 and Al . Due to great affinity of aluminium towards oxygen, it readily combines with oxygen. Hence Goldsmith used Al to reduce metal oxides in extraction. In thermite, the ratio of Fe2O3 and Al is taken 3 : 1 by weight. Fe2O3+2Al→2Fe+Al2O3(2×56+3×16=160)(2×27=54)