What is the solubility of Magnesium Pyrophospate? (Mg2P2O7)

Question

Please give answers that are theoretical. And please cite references too. Thank You

Answer 1

http://www.freepatentsonline.com/EP08704...

"...magnesium pyrophosphate (Mg2P2O7, a solubility product in water at 25 DEG C: 2.5 x 10 <-13>)..."

Mg2P2O7 --> 2moles  Mg+2 & 1 mole (P2O7)-4

"X"  dissolves giving "2x" Mg+2 & "x" (P2O7)-4

Ksp = [Mg+2]^2  [(P2O7)-4]

2.5 e-13 = [2x]^2  [x]

4x^3 =  2.5 e-13

X3 = 6,25e-14

x = [P2O7] = 3.97e-5 molar (P2O7)-4

for every mole of Mg2P2O7 that "dissolves" it releases 1 mole of (P2O7)-4

so if 3.97e-5 molar (P2O7)-4 ,... then

your answer :the solubility of Magnesium Pyrophospate is  3.97e-5 molar