72. Formation constants of HgBr3–and HgBr42–at 5°, 25°, and 35° in aqueous medium of constant ionic strength and acidity

Scaife, DE; Tyrrell, H. J. V.

doi:10.1039/jr9580000392

Cited by 6 publications

(10 citation statements)

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“…These results are not in accord with the common hypothesis of a negligibly small effect of the cation on the reversible dissociation of the dibromobromate anion [19,23,26,27]. This hypothesis was probably formulated on the basis of the results of early measurements in solvents, which stabilize the dibromobromate anion such as acetonitrile [13,24] and measurements in solvents with extensive electrolytic dissociation of salts into a cation and anion such as water and mixtures of water and organic solvents [7,20]. Indeed, in methanol, which is a solvent with high ionizing capacity, the equilibrium constants for the reversible dissociation of the dibromobromate anion measured in our laboratory and by Dubois [17] for salts with different cations are identical within experimental error.…”

Section: Resultscontrasting

confidence: 53%

Reversible dissociation of dibromobromates in organic solvents

et al. 2008

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A study was carried out on the reversible decomposition of dibromobromate anions in organic solvents and we found the equilibrium constants for the processes responsible for the distribution of active halogen and hydrogen halide between their different forms in solution. The capacity of the solvent to form hydrogen bonds with the bromide anion, the feasibility of forming a molecular complex with bromine, and the structure of the cation (in solutions with low ionizing capacity) were all found to affect the reversible decomposition of the dibromobromate anion.Organic salts with the dibromobromate anion, Br 3 − , have a set of unique properties, which open the way for their use in a very broad variety of applications [1]. The vapor pressure of bromine above solid crystalline dibromobromates is very low. Many of these salts are suitable for prolonged storage and safe for handling. Numerous studies have shown that the applicability of dibromobromates as electrolyte components for chemical power sources and materials for water purification, brominating agents differing from elemental bromine in their reaction mechanism [2, 3]. The profound differences in the reaction mechanisms of dibromobromates and bromine are seen in differing kinetic behavior, smaller reactivity and greater selectivity in the dibromobromate reactions [4][5][6]. However, there is a special feature in the behavior of dibromobromate solutions, which can cancel out all their advantages relative to molecular bromine. These complexes are capable of reversible dissociation in solution to give bromide anion and molecular bromine [1]. The state of these complexes has been studied in greatest detail for aqueous solution [1, 7-9]. There have been fewer measurements for solutions in organic solvents. Such measurements have far from always been the major concern in these studies. This perhaps accounts for the circumstance that determinations of equilibrium constants and even extinction coefficients do not always agree with one another. The formation of dibromobromates from bromide anion and bromine molecules may reliably be considered to be an exothermal [9], rapid [10] and equilibrium [1] reaction. The equilibrium constants vary in a very broad range depending on the solvent [11]. We can clearly imagine that the concentration of molecular bromine in the case of considerable dissociation of the dibromobromate anion becomes sufficient so that the contribution of the reaction involving bromine, which is much more reactive in many bromination reactions [3][4][5], becomes predominant. The advantages of using dibromobromates in this case would be eliminated. Hence, knowledge of the state of dibromobromate anions in solution is important for the application of these salts. We previously proposed bis(N,N-dimethylacetamide) hydrogen dibromobromate for use as an efficient brominating agent and component in compositions for the decomposition of toxic pollutants [12]. Not only the anion but also the cation is complex in this compound, which introduces additional complexit...

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Section: Resultscontrasting

confidence: 53%

Reversible dissociation of dibromobromates in organic solvents

et al. 2008

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“…Values for K 3 between 16.0 and 18.08 L mol À1 at 25 C are known in literature. 20,[26][27][28][29][30][31][33][34][35] For K 5 , values between 19.45 L 2 mol À2 and 40 L 2 mol À2 are reported in literature. 20,29,31,[33][34][35] Both equilibria are shied to the polybromide side and reduce free uncomplexed Br 2 in the electrolyte.…”

Section: State Of the Artmentioning

confidence: 98%

“…[23][24][25][26] is supressed in HBr for concentrations of 0.001 M or higher. [27][28][29][30][31] Solubility of Br 2 increases signicantly in aqueous bromide solutions like hydrobromic acid. Soluble polybromide complexes (eqn (2) and ( 3)), such as tribromide (Br 3 À ) or pentabromide ions (Br 5 À ) 20,28,29 are formed in an equilibrium reaction between Br 2 , bromide and the respective polybromide:…”

Section: State Of the Artmentioning

confidence: 99%

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High energy density electrolytes for H₂/Br₂redox flow batteries, their polybromide composition and influence on battery cycling limits

et al. 2021

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“…This band, which is bathochromically shifted to that of tribromide and hypsochromically relative to bromine, was assumed to be [Br 5 ] – . [Br 5 ] – was also early on discussed to be present in aqueous solutions 44,45. First vibrational studies on [Br 5 ] – were done by Evans et al33 They investigated different solutions containing potassium bromide and bromine at the ratio of 1:1 and 1:2 and observed a new Raman band at 250 cm –1 , which could be neither assigned to tribromide nor to free elemental bromine.…”

Section: Polybromidesmentioning

confidence: 99%

Recent Discoveries of Polyhalogen Anions – from Bromine to Fluorine

Haller

Riedel

2014

Zeitschrift anorg allge chemie

141

173

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In this review we discuss the recent discoveries in polyhalide anion chemistry with the main focus on polybromide, ‐chloride, and ‐fluoride anions. Based on novel synthetic strategies either in ionic liquids or in neat halogens several new polyhalides of bromine and chlorine were synthesized. Beyond these discoveries the chemistry of polyfluoride monoanions is reviewed. Such species were investigated under cryogenic conditions at 4 K in conjunction with quantum‐chemical calculations. In addition to these bonding and structural discussions, an overview of possible applications of such polyhalide anions is provided.

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72. Formation constants of HgBr₃^–and HgBr₄^2–at 5°, 25°, and 35° in aqueous medium of constant ionic strength and acidity

Cited by 6 publications

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Reversible dissociation of dibromobromates in organic solvents

Reversible dissociation of dibromobromates in organic solvents

High energy density electrolytes for H₂/Br₂redox flow batteries, their polybromide composition and influence on battery cycling limits

Recent Discoveries of Polyhalogen Anions – from Bromine to Fluorine

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72. Formation constants of HgBr3–and HgBr42–at 5°, 25°, and 35° in aqueous medium of constant ionic strength and acidity

Cited by 6 publications

References 0 publications

Reversible dissociation of dibromobromates in organic solvents

Reversible dissociation of dibromobromates in organic solvents

High energy density electrolytes for H2/Br2redox flow batteries, their polybromide composition and influence on battery cycling limits

Recent Discoveries of Polyhalogen Anions – from Bromine to Fluorine

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72. Formation constants of HgBr₃^–and HgBr₄^2–at 5°, 25°, and 35° in aqueous medium of constant ionic strength and acidity

High energy density electrolytes for H₂/Br₂redox flow batteries, their polybromide composition and influence on battery cycling limits