Nickel(II) selenate can be produced by the reaction of nickel(II) carbonate and selenic acid.

[5] Nickel(II) selenate hexahydrate is a green solid.

[6] At 100 °C, nickel(II) selenate hexahydrate slowly loses water to the tetrahydrate, with space group P21/n (No.

At 510 °C, nickel(II) selenate decomposes directly into nickel selenite, which on further heating decomposes into nickel(II) oxide and selenium dioxide.

[7][2] It and potassium selenate are cooled and crystallized in hot aqueous solution to obtain the blue-green [Ni(H2O)6](SeO4)2.