Question: what is the difference between magnesium hydroxide and magnesium oxide?
Answer: Magnesium oxide has a formula somewhat similar to that of magnesium hydroxide—it's MgO. ... As such, you can have a suspension of magnesium hydroxide in water, but you can't have a suspension of magnesium oxide in water—it would simply turn into magnesium hydroxide. Magnesium oxide is a white powder.