Complex formation in the ternary systems CaIIH4SiO4H2O and MgIIH4SiO4H2O Academic Article uri icon


  • Calcium(II) and magnesium(II) complexes of partially deprotonated H4SiO4have been investigated at 25 C in solutions of constant ClO4-molarity (1 M) by computer-controlled coulometric titration using a hydrogen electrode. The experimental data could be explained assuming the following equilibria. M2++ H3SiO4- MH3SiO4+; K1= [MH3SiO4+]/[M2+][H3SiO4-] and M2++ 2H3SiO4- M(H3SiO4)2; 2= [M(H3SiO4)2]/[M2+] [H3SiO4-]2or M2++ H2SiO42- MH2SiO4; 1= [MH2SiO4]/[M2+][H2SiO42-]. For the individual equilibrium constants, the following values were obtained: Ca2+: log K1= 0.39 (0.03); log 2= 2.89 (0.07) (log 1= 3.09) Mg2+: log K1= 0.64 (0.06); log 2= 3.82 (0.08) (log 1= 4.17).

published proceedings

  • J. Chem. Soc., Dalton Trans.

author list (cited authors)

  • Santschi, P. H., & Schindler, P. W.

citation count

  • 45

complete list of authors

  • Santschi, Peter H||Schindler, Paul W

publication date

  • January 1974