Zirconium(IV) Tetramer/Octamer Hydrolysis Equilibrium in Aqueous Hydrochloric Acid Solution

Singhal, Amit; Toth, L.M.; Lin, J. S.; Affholter, Kathleen A.

doi:10.1021/ja9602399

Cited by 183 publications

(199 citation statements)

References 14 publications

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“…The literature reports indicated that at around pH 2.0, Zr(IV) exists as coordination complex of water {e.g. Zr8 (OH)20(H2O)24Cl12}, whose geometry has been determined to be octameric [20], and under similar conditions Hf(IV) has been reported to exhibit a similar chemistry [19]. These octameric species may be formed by bridging of two tetramers via four single OH -bridges and each metal cations of the octamer would bind to three H2O molecules.…”

Section: Results and Discussonmentioning

confidence: 99%

Tetravalent Metal Catalyzed Hydrolysis of Cyanofenphos: A Delayed Neurotoxic Organophosphorus Compound

Naik¹,

YADAV²,

CP³

2011

Int J of Chem Res

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Abstract-Hydrolysis of O-ethyl O-p-cyanophenyl, phenyl phosphonothionate (Cyanofenphos) has been studied in the acidic medium with catalyst such as Zr 4+ , Ce 4+ , Hf 4+ and Th 4+ cations, and the rate maxima observed were at around pH 2.0. Since the metal aquo complex are known to exist in equilibrium with deprotonated species, and therefore metal bound OHnucleophile might be available abundantly even in acidic aqueous solutions. Thus an interaction of sulphur of P=S group with metal cation followed by an intramolecular nucleophilic attack of hydroxy anion at the ester phosphorus atom would results in the cleavage of P-O bond.

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Section: Results and Discussonmentioning

confidence: 99%

Tetravalent Metal Catalyzed Hydrolysis of Cyanofenphos: A Delayed Neurotoxic Organophosphorus Compound

Naik¹,

YADAV²,

CP³

2011

Int J of Chem Res

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“…35 In the recent years, the compositions of the Zr(IV), Hf(IV) species in chloride media have been reported in several articles. [36][37][38] In the chloride medium, the only present zirconium and hafnium substance was reported to be partly hydrolyzed as [M 4 (OH) 8 -(H 2 O) 16 Cl 6 ]…”

Section: Resultsmentioning

confidence: 99%

Liquid-liquid Distribution of the Tetravalent Zirconium, Hafnium and Thorium with a New Tetradentate Naphthol-derivative Schiff Base

2008

Bulletin of the Korean Chemical Society

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A fundamental study was developed concerning the novel solvent extraction of the tetravalent metal ions; zirconium(IV), hafnium(IV) and thorium(IV). Their extraction behavior in toluene was investigated with a recently synthesized naphthol-derivative Schiff base, 1-(The spectrophotometrical examination of the complex formation between HAPMN and the Zr(IV), Hf(IV) and Th(IV) ions in acetonitrile revealed the formation of stable 1:1 complexes in the solution. After the thorium extraction in toluene, it was found that [Th(OH) 3 HA] was the respective deriving substance. While, in the case of zirconium and hafnium extraction, the extracted adduct was found to be [M 4 (OH) 8 (H 2 O) 16 Cl 6 2HA]. The stoichiometric coefficients of these extracted species were determined by the slope analysis method. The extraction reaction followed a cation exchange mechanism.

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“…Singhal et al 24 observed that there were tetramers and octamers of zirconium in acidic aqueous solutions using smallangle X-ray scattering (SAXS). In addition, unidentified polymeric species larger than the octamer were also formed under the condition when small amounts of NaOH were added.…”

Section: Aqueous Chemistrymentioning

confidence: 99%

Colloidal Titration of Aqueous Zirconium Solutions with Poly(vinyl sulfate) by Potentiometric Endpoint Detection Using a Toluidine Blue Selective Electrode

et al. 2004

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Zirconium chemicals are used in a wide range of industries, and with advances in modern technology, the diversity of their applications has increased. 1 In particular, tetragonal zirconia is one of the most important zirconium compounds for ceramic use, with excellent mechanical properties, such as high structure toughness, strength, and hardness. 2 We have studied the effective use of some zirconium oxy-salts as a depressive and fluidizing material of ceramic slurries, 3,4 and have developed a new direct-casting method based on aqueous-acidic high solids loading alumina slurries stabilized with zirconium acetate. 5When the slurries were prepared, the concentration of zirconium oxy-salt was an important factor, and a simple and convenient determination of aqueous zirconium was required. However, the determination of zirconium is not very easy because zirconium(IV) has a marked tendency to form polynuclear hydroxy group-bridged zirconium species (polymerization) in aqueous solutions.6 Pilkington et al. mentioned that accurate results in EDTA titration of zirconium could only be obtained after zirconium ions were converted to a depolymerized form. Therefore, we studied a colloidal titration method as a means to measure the concentration of zirconium conveniently as it exists in the aqueous solution in a polynuclear configuration.Colloidal titration is an excellent measurement method for determining the concentration of natural and synthetic polyelectrolytes. [8][9][10][11][12] Titration is based on the reaction between a positively charged polyelectrolyte (polycation) and a negatively charged one (polyanion).When the charges of the polyelectrolytes are neutralized by the addition of oppositely charged polyelectrolytes, the two ployelectrolytes tend to associate and eventually precipitate. According to Terayama, who was the first proposer of colloidal titration, the colloidal titration method has been applied to several poly-charged species, such as proteins and cells. 8 However, their stoichiometries are still not clear. Regarding the reaction between oppositely charged polyelectrolytes, most of the reaction is accurately stoichiometric. As a typical case, an aqueous solution of poly(diallyldimethyl ammonium) chloride (PDADMAC) can be titrated with an aqueous solution of potassium poly(vinyl sulfate) (KPVS) of known concentration. The reaction between oppositely charged polyelectrolytes has been studied on stoichiometry, 9,13-16 the stability constant, 17,18 and the effect of the polymerization degree. 19 A few colloidal titrations were applied to measure metal ions in hydrolyzed, polymeric forms. Kikuchi and Kubota have investigated a chemical reaction of KPVS with a mixture of poly(aluminum chloride), PAC, ([Al2(OH)nCl6-n]m, n = 3, m = 2.5) as an inorganic macromolecule and [2-(diethylamino)ethyl]dextran hydrochloride.The general characteristics of the resultant polyelectrolyte complexes were also studied. 20 Tajima has reported that undeca(11-)tungstocobalt(II)phosphate, [PW11O39Co(H2O)] 5-, was a useful standa...

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Zirconium(IV) Tetramer/Octamer Hydrolysis Equilibrium in Aqueous Hydrochloric Acid Solution

Cited by 183 publications

References 14 publications

Tetravalent Metal Catalyzed Hydrolysis of Cyanofenphos: A Delayed Neurotoxic Organophosphorus Compound

Tetravalent Metal Catalyzed Hydrolysis of Cyanofenphos: A Delayed Neurotoxic Organophosphorus Compound

Liquid-liquid Distribution of the Tetravalent Zirconium, Hafnium and Thorium with a New Tetradentate Naphthol-derivative Schiff Base

Colloidal Titration of Aqueous Zirconium Solutions with Poly(vinyl sulfate) by Potentiometric Endpoint Detection Using a Toluidine Blue Selective Electrode

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