The effect of calcium and magnesium ions on calcium pyrophosphate crystal formation in aqueous solutions

J Rheumatol. Sep-Oct 1981;8(5):772-82.


Calcium pyrophosphate crystal formation has been associated clinically with hypercalcemic states (hyperparathyroidism) and hypomagnesemia. We studied aqueous solutions at pH 7.4, 37 degrees C, [Na+] = 140 nM over a range of calcium chloride/magnesium chloride/sodium pyrophosphate concentrations to determine the effect of calcium and magnesium ions on crystal formation. We found that CPPD(T) and CPPD(M) could form under different ionic conditions. Low [Mg++] and [PPi] favoured CPPD(T) whereas higher [Mg++] and [PPi] favoured CPPD(M). At [Mg++] = 1.0 mM a calcium magnesium pyrophosphate crystal phase designated CMPP2 formed. As [Mg++] affects the crystal phase formed more than equimolar [Ca++], we conclude that ionic magnesium deficiency may be a clinically important determinant in calcium pyrophosphate dihydrate crystal formation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium / pharmacology*
  • Calcium Pyrophosphate*
  • Chemical Phenomena
  • Chemistry
  • Crystallization
  • Diphosphates*
  • Magnesium / pharmacology*
  • Solutions
  • Time Factors
  • Water


  • Diphosphates
  • Solutions
  • Water
  • Magnesium
  • Calcium
  • Calcium Pyrophosphate