Magnesium nitrite trihydrate is a combination of magnesium nitrite and water, as represented by the formula Mg(NO2)2.3H2O. Magnesium nitrite trihydrate is formed when a molecule of magnesium nitrite crystallizes with three molecules of H2O.
As the solution of magnesium nitrite trihydrate decomposes, it eventually separates out, so that when the water is evaporated, it produces nitric oxide. The compound can be produced through a reaction of barium nitrite and magnesium sulphate or from a reaction of silver nitrite with either magnesia or magnesium chloride. It's crystalline form is yellow and white. Magnesium nitrite has a molar mass of about 116.31 grams per mole.