title: Complexation of UVI with 1-hydroxyethane-1,1-diphosphonic acid in acidic to basic solutions.
abstract: Complexation of UVI with 1-hydroxyethane-1,1-diphosphonic acid (HEDPA) in acidic to basic solutions has been studied with multiple techniques. A number of 1:1 (UO2H3L), 1:2 (UO2HjL2 where j = +4, +3, +2, +1, 0, and -1), and 2:2 [(UO2)2HjL2 where j = +1, 0, and -1] complexes form, but the 1:2 complexes are the major species in a wide pH range. Thermodynamic parameters (formation constants and enthalpy and entropy of complexation) were determined by potentiometry and calorimetry. Data indicate that the complexation of UVI with HEDPA is exothermic, favored by the enthalpy of complexation. This is in contrast to the complexation of UVI with dicarboxylic acids in which the enthalpy term usually is unfavorable. Results from electrospray ionization mass spectrometry and 31P NMR have confirmed the presence of 1:1, 1:2, and 2:2 UVIHEDPA complexes.
authors.affiliation: Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Wendy A
authors.initials: WA
authors.lastname: Reed
authors.forename: Linfeng
authors.initials: L
authors.lastname: Rao
authors.forename: PierLuigi
authors.initials: P
authors.lastname: Zanonato
authors.forename: Alexander Yu
authors.initials: AY
authors.lastname: Garnov
authors.forename: Brian A
authors.initials: BA
authors.lastname: Powell
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Nash
mesh_terms: D000143:Acids / Q000737:chemistry*; D012968:Etidronic Acid / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D011522:Protons; D012996:Solutions / Q000737:chemistry; D013057:Spectrum Analysis; D017186:Titrimetry
chemical_list: D000143:Acids; D011522:Protons; D012996:Solutions; D012968:Etidronic Acid