Mercuric oxide red can be made by heating Hg in oxygen at roughly 350 °C, or by pyrolysis of Hg(NO3)2.Soluble in dilute hydrochloric acid and nitric acid. Insoluble in water, ethanol and ether.
Mercuric oxide red has a formula of HgO. It is dense orangish-red powder that turns yellow when finely powdered. .Mercury(II) oxide is a solid at room temperature and pressure.