Kainotropite is a rare vanadate mineral with the formula Cu<sub>4</sub>FeO<sub>2</sub>(V<sub>2</sub>O<sub>7</sub>)(VO<sub>4</sub>). It contains trivalent iron. It is one of many fumarolic minerals discovered on the Tolbachik volcano. The name of its parental fumarole is "Yadovitaya", which means poisonous.
Structure of kainotropite is unique. However, there are other minerals containing both copper and divanadate group, like engelhauptite and volborthite.