Chemical reactions of the elements
Reaction of mercury with air
Mercury metal reacts in air at about 350°C to form mercury(II) oxide.
2Hg(s) + O2(g) → 2HgO(s) [red]
Reaction of mercury with water
Mercury does not react with water under normal conditions.
Reaction of mercury with the halogens
Mercury metal reacts with fluorine, F2, chlorine, Cl2, bromine, Br2, or iodine, I2, to form the dihalides mercury(II) fluoride, HgF2, mercury(II) chloride, HgCl2, mercury(II) bromide, HgBr2, or mercury(II) iodide, HgI2, respectively.
Hg(l) + F2(g) → HgF2(s) [white]
Hg(l) + Cl2(g) → HgCl2(s) [white]
Hg(l) + Br2(l) → HgBr2(s) [white]
Hg(l) + I2(s) → HgI2(s) [red]
Reaction of mercury with acids
Mercury does not react with non-oxidizing acids but does react with concentrated nitric acid, HNO3, or concentrated sulphuric acid, H2SO4, to form mercury(II) compounds together with nitrogen or sulphur oxides.
Mercury dissolves slowly in dilute nitric acid to form mercury(I) nitrate, mercurous nitrate, Hg2(NO3)2.
Reaction of mercury with bases
Mercury does not react with alkalis under normal conditions.