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Hydration, solvation and hydrolysis of multicharged metal ions

Torapava, Natallia (2011). Hydration, solvation and hydrolysis of multicharged metal ions. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2011:65
ISBN 978-91-576-7609-2
[Doctoral thesis]

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Abstract

Structures of hydrated, solvated and hydrolyzed multicharged metal ions are determined by EXAFS and LAXS in solution, and by X-ray crystallography and EXAFS in the solid state.

During hydrolysis, the nine-coordinate hydrated thorium(IV) ion is first transformed to a dimer, [Th₂(μ²-OH)₂(H₂O)₁₂]⁶⁺, then to a tetramer, [Th₄(μ²-OH)₈(H₂O)₁₆]⁸⁺, and finally to a hexamer, [Th₆(μ³-O₈)(H₂O)n]⁸⁺ with increasing pH and thorium(IV) concentration in an aqueous solution. Coordinated water looses the protons in two steps, first with the formation of the dimer and tetramer, and finally with the formation of the hexamer.

Together thorium(IV) and iron(III) form a stable and highly soluble heteronuclear hydrolysis complex, [Th₂Fe₂(μ²-OH)₈(H₂O)₁₂]⁶⁺, in the pH range 2.9 - 4.8 and metal concentrations 0.02 – 0.4 mol·dm⁻³. In the same solutions at pH < 2.9 two- or six-line ferrihydrite precipitates with time, while thorium(IV) remains in solution.

Palladium(II) and platinum(II) hydrolyze very slowly in acidic aqueous solution and after 25 years of storage tiny oxide-like particles are formed at pH = 0.7. The particle size has been estimated from the number of M···M distances in the formed particles and in the corresponding solid oxides from EXAFS studies. The palladium(II) and platinum(II) oxide particles grow along a or b axies and reach a size of 1 - 1.5 nm³. These results have been supported by SAXS studies.

During hydrolysis, the six-coordinate hydrated chromium(III) ion is first transformed to a dimer, then to a tetramer, [Cr₄(μ²-OH)₂(μ-OH)₄(OH)n(H₂O)₁₂-n](6-n)+ with increasing pH from 0 to 3.7 at chromium concentration of ca. 1 mol·dm⁻³. At pH  15, soluble [Cr(μ²-OH)₂(OH)₂]nn-, n  3, complex is formed, which at pH < 15 slowly precipitates as an amorphous solid with a structure similar to α-CrOOH.

Dimethylsulfoxide (DMSO) solvated thorium(IV) is nine-coordinate both in solution and solid state. N,N’-Dimethylpropyleneurea (DMPU) solvated thorium(IV) is eight-coordinate in solution. The lower coordination number is due to the space-demanding properties of the DMPU molecules upon coordination.

Authors/Creators:Torapava, Natallia
Title:Hydration, solvation and hydrolysis of multicharged metal ions
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :26 August 2011
Volume:2011:65
Number of Pages:66
Papers/manuscripts:
NumberReferences
I.Torapava, N.; Persson, I.; Eriksson, L.; Lundberg, D. Hydration and hydrolysis of thorium(IV) in aqueous solution and the structures of two crystalline thorium(IV) hydrates. Inorganic Chemistry 2009, 48, 11712-11723.
II.Torapava, N.; Radkevich, A.; Persson, I.; Davydov, D.; Eriksson, L. Formation of a heteronuclear hydrolysis complex in the ThIV/FeIII system. Submitted to Dalton Transactions.
III.Torapava, N.; Elding, L. I.; Mändar, H.; Roosalu, K.; Persson, I. Hydrolysis of palladium(II) and platinum(II) in acidic aqueous solution. (manuscript).
IV.Torapava, N.; Radkevich, A.; Davydov, D.; Titov, A.; Persson, I. Composition and structure of polynuclear chromium(III) hydroxo complexes. Inorganic Chemistry 2009, 48, 10383-10388.
V.Torapava, N.; Lundberg, D.; Persson, I. A Coordination Chemistry Study of the solvated thorium(IV) ion in two oxygen donor solvents. Accepted for publication in European Journal of Inorganic Chemistry.
VI.Abbasi, A.; Skripkin, M. Yu.; Eriksson, L.; Torapava, N. Ambidentate coordination of dimethyl sulfoxide in rhodium(III) complexes. Dalton Transactions 2011, 40, 1111-1118.
Place of Publication:Uppsala
Publisher:Institutionen för kemi, Sveriges lantbruksuniversitet
ISBN for printed version:978-91-576-7609-2
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:X Agricola extesions > X50 Chemistry
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 104 Chemical Sciences > Inorganic Chemistry
Agrovoc terms:ions, metallic elements, hydration, hydrolysis, chemical structure, analytical methods
Keywords:hydration, hydrolysis, EXAFS, LAXS, metal ions
URN:NBN:urn:nbn:se:slu:epsilon-e-191
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-191
ID Code:8299
Department:(NL, NJ) > Dept. of Chemistry (until 131231)
Deposited By: Ms Natallia Torapava
Deposited On:30 Aug 2011 09:28
Metadata Last Modified:02 Dec 2014 10:47

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