Manganese nitrate solution 10%, Manganese(II) nitrate are the inorganic compounds with formula Mn(NO₃)₂·ₙ. Each formula unit is composed of one Mn²⁺ cation and two NO₃⁻ anions and varying amounts of water. Most common is the tetrahydrate Mn(NO₃)₂·4H₂O, but mono- and hexahydrates are also known as well as the anhydrous compound