3 Mg(OH)2 + 2 H3PO3 → 6 H2O + Mg3(PO3)2
Reactants:
- Mg(OH)2 – Magnesium hydroxide


- Other names: Magnesium dihydroxide

, Milk of magnesia 
, Magnesia, [Milk of]
Mg(OH)2
, Magnesium hydrate 
- Appearance: White solid

- H3PO3 – Phosphonic acid


- Other names: Phosphorous acid
, Dihydroxyphosphine oxide 
- Appearance: White solid | deliquescent

Products:
- H2O – Water, oxidane

- Other names: Water (H2O)
, Hydrogen hydroxide (HH or HOH)
, Hydrogen oxide
Dihydrogen monoxide (DHMO) (systematic name)
, Hydrogen monoxide
, Dihydrogen oxide
, Hydric acid
, Hydrohydroxic acid
, Hydroxic acid
, Hydrol
, Μ-oxido dihydrogen
, Κ1-hydroxyl hydrogen(0) 
- Appearance: White crystalline solid, almost colorless liquid with a hint of blue, colorless gas

- Mg3(PO3)2