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Publication Type
Journal Article
Author, Analytic
Abdur-Rashid, Kamaluddin; Dasgupta, Tara, P.; Burgess, John
Author Affiliation, Ana.
Chemistry; Faculty of Pure and Applied Sciences
Article Title
Reactivity of the Tri-m-hydroxo-bis[triamminecobalt(III)] Ion in halide media
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Connective Phrase
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Journal Title
Journal of the Chemical Society. Dalton Transactions
Translated Title
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Reprint Status
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Date of Publication
1994
Volume ID
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Issue ID
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Page(s)
2327
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ISSN
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Notes
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Abstract
The kinetics of acid hydrolysis of trans-[(H2O)(NH3)3Co( m-OH)2Co(NH3)3(H2O)]4+ in acidic chloride and bromide solutions was studied using stopped-flow and conventional spectrophotometric techniques, at an ionic strength of 1.0 mol dm-3 and over the ranges 0.10 [H+] 0.50 mol dm-3, 0.10 [X-] 0.50 mol dm-3, 25 T 35 C and in binary aqueous cosolvent mixtures containing up to 40% methonol by volume. The rate equation observed was of the form kobs= (kc[H+] +kc) [X-]. At 25 C the rate constants kc were 1.10 x10-2 and 1.22 x 10-3 dm6 mol-2 s-1 in chloride and bromide solutions respectively for the [H+]- dependent term. The corresponding values for the [H+]-independent pathway, kc were 4.5 x 10-4 and 0.7 x 10-4 dm3 mol-1 s-1. The activation parmeters in chloride solution were D H (kc ) = 51 14 kJ mol-1, D S (kc ) = -110 48 J K-1 mol-1; DH (kc) = 132 32 kJ mol-1 and DS (kc) = 136 105 J K-1 mol-1. At constant [H+] (0.5 mol dm-3) the reaction was first order with respect to [Cl-] and [Br-] and the rate constants, kd, were 4.5 x 3.3 x 10-3 dm-3 mol-1 s-1 respectively....
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