The main difference between Sulfate and Sulfide is that the Sulfate is a anion and Sulfide is a chemical compound.
The sulfate or sulphate (see spelling differences) ion is a polyatomic anion with the empirical formula SO2−4. Sulfate is the spelling recommended by IUPAC, but sulphate is used in British English. Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many are prepared from that acid.
Sulfide (systematically named sulfanediide, and sulfide(2−)) (British English sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. It contributes no color to sulfide salts. As it is classified as a strong base, even dilute solutions of salts such as sodium sulfide (Na2S) are corrosive and can attack the skin. Sulfide is the simplest sulfur anion.
Any ester of sulfuric acid.
Any salt of sulfuric acid.
To treat something with sulfuric acid, a sulfate, or with sulfur dioxide.
To accumulate a deposit of lead sulfate.
Any compound of sulfur and a metal or other electropositive element or group.