Cu2S2 is actually not an existing chemical compound. In chemistry, there is no compound with the formula Cu2S2. For copper (Cu) and sulfur (S), the most common compounds they form are Cu2S (copper sulfide) and CuS (copper monosulfide).
Cu2S, also known as copper(I) sulfide, or simply copper sulfide, is a chemical compound of copper and sulfur. In English, it is called copper(I) sulfide or copper sulfide. The atomic mass of Cu is 63.55 and of S is 32.07, therefore the atomic mass of Cu2S is (63.55 x 2) + 32.07 = 159.17.
Cu2S is black or pale green in color. It has no smell and its pH value cannot be determined as it is insoluble in water. In chemistry, Cu2S can react with oxygen or acid to form other compounds.
Additionally, CuS, also known as copper(II) sulfide, is black in color and has similar properties to Cu2S. Reactions of CuS usually occur in acidic or oxygen environments, producing other compounds such as SO2, CuSO4, and many other compounds.
It should be remembered that there is no chemical compound with the formula Cu2S2. This could be a typo or misunderstanding.