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Physical & Chemical properties

Water solubility

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Description of key information

A definitive the water solubility of bismuth trinitrate cannot be estabilised (see discussion). For the purposes of risk assessment, it may be assumed that bismuth nitrate is moderately soluble to soluble, having in mind that - based on the chemistry of bismuth - a defined water solubility cannot be established and that actual dissolved concentrations of bismuth depend on a number of parameters, such as total concentration, pH, ionic environment etc.

Key value for chemical safety assessment

Water solubility:
50 mg/L
at the temperature of:
20 °C

Additional information

In an attempt to establish the water solubility of bismuth trinitrate, a guideline study (OECD 105) has been conducted with bismuth trinitrate hydrate, which is the form commercially available on the market (Paulus, 2010, see endpoint study record). Within the test period of 8 days, the measured concentrations of dissolved Bi varied from ca. 26 mg/L to 1150 mg/L, corresponding to a apparent water solubilities of the test item in the range of 50.0 -2180 mg/L at 20 +/- 0.5°C. No clear trends (e.g. constant increase) not saturation was observed. A definitive water solubility of bismuth trinitrate cannot be established in this study.

Based on these finding, a brief literature search on the solubility of bismuth nitrate was conducted and chemical textbooks were consulted, which seem to offer some further explanation: According to Smith (1973, cited in Heinemann 1995), bismuth salts are rapidly hydrolysed on aqueous media and form less soluble precipitates. Further, according to Holleman and Wiberg (1995), bismuth can be coordinated in solutions in various ways by OH[-] or O[2 -] ions. A multitude of mono- or polynuclear, hydrated Bi species exist, with the equilibrium between them depending on total concentrations, pH and possibly other ions in the solution. This may explain that a definitive water solubility of bismuth trinitrate cannot be established.

For the purposes of risk assessment, it may be assumed that bismuth nitrate is moderately soluble to soluble, having in mind that - based on the chemistry of bismuth - a defined water solubility cannot be established and that actual dissolved concentrations of bismuth depend on a number of parameters, such as total concentration, pH, ionic environment etc.

References:

Smith (1973); In: Comprhensive Inorganic Chemistry, vol. 2, ed. Bailar, J.D.; et al.; Pergamon Press, Oxford, pp 547 -683

Heinemann (1995); Influence of hydroxycarboxylic acids on the water solubility of various bismuth compounds. Arzneimittel-Forschung 45, 48-51

Holleman, A.F.; Wiberg, E. (1995); In: Lehrbuch der anorganischen Chemie. de Gruyer, 101. edition