Cobalt(II) sulfate is any of the inorganic compounds with the formula CoSO 4 (H 2 O) x . Usually cobalt sulfate refers to the hexa- or heptahydrates CoSO 4 . 6H 2 O or CoSO 4 . 7H 2 O, respectively. The heptahydrate is a red solid that is soluble in water and methanol. Since cobalt(II) has an odd number of electrons, its salts are paramagnetic.