Cu2S
The cuprous sulfide - Cu2S - is black.
The chemical formula for cuprous arsenide is Cu3As.
The chemical formula for cuprous fluoride is CuF.
The formula for cuprous hydrogen carbonate is Cu(HCO3)2.
The formula for ammoniacal cuprous chloride is CuCl.NH3.
The formula for cesium sulphide is Cs2S.
The mass of a formula unit of cuprous sulfide (Cu2S) is 159.152 g/mol.
The chemical formula for cuprous phosphate is Cu3(PO4)2.
The formula for lithium sulphide is Li2S.
CuI
Actually, the answer Cu(NO3)2 is incorrect for cuprous nitrate. Cu(NO3)2 is in fact cupric nitrate. Cuprous nitrate is represented as CuNO3 alone.
The formula for Lead Sulfide (or Lead Sulphide) is either: PbS for Lead(II) Sulphide, or PbS2 for Lead(IV) Sulphide.