Firstly, we need to understand that HgO2 is not a compound that exists in reality. In fact, the mercury element (Hg) when combined with oxygen (O) usually forms two main compounds, namely HgO (mercury(II) oxide) and Hg2O (mercury(I) oxide). Therefore, I will introduce HgO, mercury(II) oxide, a common compound of mercury and oxygen.
HgO, also known as mercury(II) oxide or yellow mercuric oxide in English. The atomic mass of Hg is 200.59 and O is 16, thus the atomic mass of HgO is 216.59. The HgO molecule consists of one mercury atom linked to one oxygen atom.
In terms of properties, HgO is a bright yellow or red powder and does not have a specific smell. HgO is insoluble in water and common solvents, but soluble in acid.
HgO can react with strong acids such as hydrochloric acid to form mercury(II) chloride salt and water, or react with metals like the Al compound to produce the mercury compound Al2HgO2.
In the laboratory, HgO can be synthesized from pure mercury and oxygen by heating the mercury in the air.
On an industrial scale, HgO is usually produced by oxidizing mercury with nitric acid or by thermal decomposition of mercury(II) nitrate salt.
I hope that the students have gained a better understanding of the HgO compound through this lecture.