(Q&A) What are the names of these compounds? They are: S2Cl2 and Hg2Cl2.?

Q=
What are the names of these compounds? They are: S2Cl2 and Hg2Cl2.?

A=
S2Cl2 = disulfur dichloride, Cl-S-S-Cl

Hg2Cl2 = mercury (I) chloride

The mercury (I) cation is Hg2^2+. It is sort of a diatomic ion. In the +1 oxidation state there is no single Hg. In other words, HgCl does not exist. HgCl2 does exist, except in this case, mercury is in the +2 oxidation state.

The only thing you have to remember is that there are no single mercury (I) ions, mercury (I) exists as Hg2^2+.

========= Follow up =========

I don't think Hg2Cl2 will be very ionic, what with an electronegativity difference of 1.16. That translates to a percent ionic character of 28.6 for the Hg-Cl bond.

Hg2Cl2 would NOT be named mercury chloride. Mercury requires a Roman numeral in the stock system.

Or you could name Hg2Cl2 as mercurous chloride.