2Fe + 14NaOH + 3Br2 + 2H2O 2Na4[Fe(H2O)(OH)7] + 6NaBr
Iron react with sodium hydroxide, bromine and water to produce heptahydroxoaquaferrate(III) sodium and sodium bromide. Sodium hydroxide - 50% solution. This reaction takes place at a temperature of 50-60°C.