Wow, ok, that helps a LOT!! I guess you can't very easily balance an equation that can never happen! :) Thanks a lot! Just to make things clear, wouldn't it have to be Mg3(PO4)2, from balancing the charges?
Phosphoric acid reacts with magnesium hydroxide to produce magnesium phosphate and water via the following reaction:H3PO4 + Mg(OH)2 -----> Mg3(PO4)2 + H2O.Balance the equation, then enter the coefficients