title: Structural characteristics of amorphous K-Bi citrate (De-Nol) and its aqueous solutions from EXAFS spectra.
abstract: EXAFS (Extended X-ray Absorption Fine Structure) spectra of an amorphous solid Bi complex with citrate (known as De-Nol) and its aqueous solutions in a wide concentration range are measured. For the solutions good agreement is revealed between their structural parameters and the averaged interatomic distances and coordination numbers of the crystalline polymeric bismuth citrate compound composed of 12-nuclear Bi clusters based on the structure Bi12O22. So, it is found that droplets of the colloidal solution have a core structure close to the solid Bi12O22cluster structure. When the concentrated solution is diluted the cluster structure is somewhat modified, it remaining similar to the structure of the Bi12O22cluster and even at a tenfold dilution and the nearest (oxygen) spheres of the Bi environment changing insignificantly. The appearance in this case of an additional oxygen atom at a large distance from the bismuth atom likely due to the presence of the oxygen atom from the hydroxyl group of the diluted aqueous solution. The appearance of such oxygen is in accordance with particles size increase for diluted solution obtained by small-angle X-ray diffraction measurements. It is established that the structure of the amorphous solid complex is multiphase and, as a whole, similar to the structure of the solid binuclear complexes.
authors.affiliation: Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia; Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia. Electronic address: simon@niic.nsc.ru.
authors.forename: Simon B
authors.initials: SB
authors.lastname: Erenburg
authors.affiliation: Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia. Electronic address: svt@niic.nsc.ru.
authors.forename: Svetlana V
authors.initials: SV
authors.lastname: Trubina
authors.affiliation: Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia. Electronic address: yukhin@solid.nsc.ru.
authors.forename: Yuri M
authors.initials: YM
authors.lastname: Yukhin
authors.affiliation: Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia. Electronic address: marat@solid.nsc.ru.
authors.forename: Marat R
authors.initials: MR
authors.lastname: Sharafutdinov
mesh_terms: D001729:Bismuth / Q000737:chemistry*; D002951:Citrates / Q000737:chemistry*; D015394:Molecular Structure; D011188:Potassium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D002951:Citrates; D011188:Potassium; D001729:Bismuth
keywords: Colloidal solution; De-Nol; EXAFS; Microstructure