cobalt (II), polyligand complex, composition, stability constant, spectro­photometry.

How to Cite

Nikitenko, V., Kublanovsky, V., & Yapontseva, Y. (2022). DETERMINATION OF POLYLIGAND COMPLEXES OF COBALT (II) WITH CITRATE AND PYROPHOSPHATE IONS. Ukrainian Chemistry Journal, 88(4), 113-122.


In the work it is shown by the spectrophotometry method that depending on the concentration ratio of ligands [PPi4–]/[Cit3–] in the pyrophosphate-citrate electrolyte, cobalt (II) ions form not only citrate [Co(Cit)2]4– and pyrophosphate [Co(PPi)2]6–, but also polyligand complexes [Co(PPi)m(Cit)n]+2–(4m+3n). The composition of polyligand complexes [Co(PPi)Cit]5– was determined, and the equilibrium constant of the reaction of their formation and the constant of their stability were calculated (pβ=8.47). The dependence of the degree of formation of citrate, polyligand, and pyrophosphate complexes of cobalt (II) in the pyrophosphate-citrate electrolyte on the logarithm of the ratio of equilibrium concentrations of ligands is calculated.


Yapontseva Y.S., Маltseva T.V. Кublanovsky V.S. Corrosion Properties of Electrolytic Coa­tings Based on СоW, CoRe, and CoWRe Alloys. Mater Sci. 2021. 56: 649–653.

Eliaz N., Gileadi E. Induced codeposition of alloys of tungsten, molybdenum and rhenium with transition metals, in: C.G. Vayenas, R.E. White, M.E. Gamboa-Aldeco (Eds.), Modern Aspects of Electrochemistry. 42. Springer, New York. 2008. P. 191 (Chapter 4).

Yapontseva Yu. S., Maltseva T.V., Kublanovsky V.S., Vyshnevskyi O.A. Electrodeposition of CoWRe alloys from polyligand citrate-pyrophosphate electrolyte. J. Alloys Compd. 2019. 803: 1–8.

Vernickaite E., Tsyntsaru N., Sobczak K., Cesiulis H. Electrodeposited tungsten-rich Ni-W, Co-W and Fe-W cathodes for efficient hydrogen evolution in alkaline medium. Electrochimica Acta. 2019. 318: 597.

Yapontseva Yu., Maltseva T., Kublanovsky V. Electrosynthesis of nanostructured thin coatings with superalloys CoW, CoRe and CoWRe with valuable properties in hardness and corrosion Resistance. Materials Today: Proceedings. 2021. 35: 584–587.

Naor A., Eliaz N., Gileadi E. Electrodeposition of Alloys of Rhenium with Iron-Group Metals from Aqueous Solutions J. Electrochemical Society. 2010. 157: 422.

Naor A., Eliaz N., Gileadi E. Electrodeposition of rhenium–nickel alloys from aqueous solutions. Electrochimica Acta. 2009. 54: 6028.

Silkin S. A., Belevskii S. S., Tsyntsaru N. I. et al., Shul’man A. I., Shchuplyakov A. N., and Dikusar A. I. Influence of Long-Term Operation of Electrolytes on the Composition, Morphology, and Mechanical Properties of Surfaces Produced at Deposition of Co–W Coatings from Citrate Solutions. Surface Engineering and Applied Electrochemistry. 2009. 45 (1): 1.

Tsyntsaru N., Cesiulis H., Donten M. et al., Sort J., Pellicer E., Podlaha-Murphy E. J. Mo­dern Trends in Tungsten Alloys Electrodeposition with Iron Group Metals. Surface Engineering and Applied Electrochemistry. 2012. 48(6): 491.

Gapon Ju.K., Sahnenko N.D., M.V. Ved', Nenastina T.A. Zakonomernosti obrazovanija kompleksov kobal'ta (II). Vіsnyk NTU HPІ. 2014. 51: 136 (іn Russian).

Sillen L.G., Martell A. E. Stability Constants of Metal–Ion Complexes and Supplement. Special Publications No. 17 and 25. London: The Chemical Society. 1964. 1. 1971: 2.

Zhao-Hui, Yuan-Fu Dong, and Hui-Lin Wan. Structural Diversities of Cobalt(II) Coordination Polymers with Citric Acid. Crystal Growth & Design. 2005. 5 (3): 1109.

Galloway K. W., Whyte A. M., Wernsdor­fer W., Sanchez-Benitez J., Kamenev K. V., Parkin A., Peacock R. D., Murrie M. Cobalt(II) Citrate Cubane Single-Molecule Magnet. Inorg. Chem. 2008. 47: 7438.

Kotsakis N., Raptopoulou C.P., Tangoulis V., Terzis A., Giapintzakis J., Jakusch T., Kiss T., Salifoglou A. Correlations of Synthetic, Spectroscopic, Structural, and Speciation Studies in the Biologically Relevant Cobalt(II)-Citrate System: The Tale of the First Aqueous Dinuclear Cobalt(II)-Citrate Complex. Inorg. Chem. 2003. 42: 22.

Matezapetakis M., Dakanali M., Raptopoulou C.P. et al. Tangoulis V., Terzis A., Moon N., Giapintzakis J., Sulifoglou A. Synthetic, Spectroscopic, and Structural characterization of the first aqueous Cobalt(II)-Citrate complex: toward a potentially bioavailable form of cobalt in biologically relevant fluids. JBIC. 2000. 5: 469.

Wyrzykowski D., Chmurzynski L. Thermodynamics of Citrate complexation with Mn2+, Co2+, Ni2+ and Zn2+ ions J. Therm. Anal. Calorim. 2010. 102: 61.

Babko A.K. Physicochemical analysis of complex compounds in solutions. Kyiv: Publishing House of the USSR Academy of Sciences, 1955 (іn Russian).

H.L. Schläfer, Komplexbildung in Lösung. Springer-Verlag: Berlin, Göttingen, Heidelberg. 1961 (in German).

Kravtsov V.I. Equilibrium and kinetics of electrode reactions of metal complexes. Khimiya, Leningrad. 1985 (іn Russian).

Kratkij spravochnik po himii. Eds. O.D. Kurilenko. K.: Nauk. dumka. 1974 (іn Russian).

Beck M., Nagypal I. Chemistry of complex equilibria. Budapest: Akademiai Kiado. 1989.

Drago R.S. Physical methods in chemistryю Saunders company: Philadelphia, London, Toronto. 1978.

Babko A.K., Pilipenko A.T. Kolorimetricheskij analiz. M.: L.: GNTI. 1951 (іn Russian).

Babko A.K., Pjatnickij I.V. Kolichestvennyj analiz. M.: Vysshaja shkola. 1962 (іn Russian).

Spektroskopicheskie metody v himii kompleksnyh soedinenij. Eds. V.M. Vdovenko. M., L.: Himija. 1964 (іn Russian).

Rossotti F.J.C., Rossotti H. The determination of stability constants and other equilibrium constants in solution. McGraw-Hill book company: New York, Toronto, London, 1961.

Newman L., Hume D.N. Determination of Successive Formation Constants by Spectrophotometry. J. Amer. Chem. Soc. 1957. 79: 4571.

Watters J.I., Mason J., Aaron A. J. Spectrophotometric Investigation of the Mixed Complex Formed by Copper Ions with Ammonium and Pyrophosphate ions in Aqueous Solutions J. Amer. Chem. Soc. 1953. 75: 5212.


Download data is not yet available.