They are divided into 4 main groups as compound fertilizers.
NITROGEN FERTILIZERS
Ammonium sulfate
Ammonium nitrate
Urea
PHOSPHORUS FERTILIZERS
Superphosphate
Triple superphosphate
POTASSIUM FERTILIZERS
potassium sulfate
potassium nitrate
COMPOSED FERTILIZERS
Compound fertilizers contain more than one plant nutrients together. The plant nutrients in the compound fertilizer are nitrogen, phosphorus and potassium. These are expressed as % in order.
Diammonium phosphate fertilizer is also a compound fertilizer. It is popularly called DAP.