Equilibrium Constants of the Complexation of Molybdate Ion with para-Sulfonatocalix [4] arene in aqueous media

Document Type : Research Paper




The complexation of sodium molybdate with para-sulfonatocalix [4] arene was studied in the
temperature range from 20 to 40 °C and pH = 5.8 by spectroscopic method in water solution. The
stability constants of complexes were calculated by the multiwavelength analysis of spectral data
using SQUAD program. The equilibrium constant, spectroscopic data, molar absorptivities and
concentrations of all species were adequately optimized by program when the chemical model
with 1:1 stoichiometry was considered in the calculation. The extracted values of molar
absorptivities and concentration- profile of the formed complex were reported. The logarithms of
the stability constants of complexes were calculated to be 3.672, 3.143, 2.986, 2.555, and 2.333
at20, 25, 30, 35and 40 °C respectively