Mercury(I) oxide, also known as mercurous oxide, is an inorganic metal oxide with the chemical formula Hg₂O. It is a brown/black powder, insoluble in water but soluble in

nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available ni ...

. With

hydrochloric acid Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid. It is a component of the gastric acid in the dige ...

, it reacts to form calomel, Hg₂Cl₂. Mercury(I) oxide is toxic but without taste or smell. It is chemically unstable and converts to

mercury(II) oxide Mercury(II) oxide, also called mercuric oxide or simply mercury oxide, is the inorganic compound with the formula Hg O. It has a red or orange color. Mercury(II) oxide is a solid at room temperature and pressure. The mineral form montroydite is v ...

and mercury metal.

References

Oxides Mercury(I) compounds Inorganic compounds {{Inorganic-compound-stub