Supersaturation functions in binary solid solution–aqueous solution systems

Astilleros, José Manuel; Pina, Carlos M.; Fernández-Dı́az, Lurdes; Putnis, Andrew

doi:10.1016/s0016-7037(02)01166-3

Cited by 47 publications

(30 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The retardation of the step velocity for each subsequent layer has been sys tematically examined as a function of aqueous solution concentration, together with calculations of the supersaturation of the aqueous solution with respect to the whole solid solution, using methods described by Astilleros et al [17]. All the results indicate that the growth of the first mono- layer on the original substrate produces a new surface with modified properties, most likely due to compositional differences with respect to the initial surface and the resultant lattice misfits.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Nanoscale growth of solids crystallising from multicomponent aqueous solutions

et al. 2003

View full text Add to dashboard Cite

The effect of 'foreign' ions on the growth of pure crystals from aqueous solution is an important topic addressed by both crystal growth, mineral and surface sciences. However, many aspects of the role played by those ions remain unclear. Our atomic force microscope (AFM) observations of the propagation of monomolecular steps of crystals in solid solution-aqueous solution (SS-AS) systems show that step velocities are determined by the surface structure of the underlying layer, so that each new growth layer exerts a decisive influence on subsequent layers. Moreover, we show that our observations cannot be completely explained by present crystal growth models based on either the pinning of elementary step motion by impurities or changes in free energy by incorporation of different cations into the lattice. A 'surface strain relaxation' model is proposed to explain the experimental observations. Our results, apart from providing an alternative explanation for the development of "dead zones", can shed light on poorly understood phenomena such as the development of compositional zoning in crystals.

show abstract

Section: Resultsmentioning

confidence: 99%

“…For SS-AS systems, supersaturation cannot be expressed by a unique value, but is a function of the composition of both solid and aqueous phases (see Fig. 4, [17]). In fact, an aqueous solution can be undersaturated with respect to a pure phase and supersaturated with respect to a more soluble solid solution.…”

Section: Discussionmentioning

confidence: 99%

Nanoscale growth of solids crystallising from multicomponent aqueous solutions

et al. 2003

View full text Add to dashboard Cite

show abstract

“…the aqueous ion activ ity product at equilibrium. Applying this expression to the binary solid solution BaxSr' -xS04, and taking into account the Lippmann and Debye -Hiickel methods (extensively described in Glynn & Reardon (1990) and in Prieto et al (1989,1991 ) Recently, an alternative, more general expression for supersaturation has been derived directly from the two conditions of thermodynamic equilibrium for such systems (5.1) (Astilleros et al 2002). If the composition of a given aqueous solution is expressed as an activity fraction [Ba2+] I[Ba2+] +[Sr2+], then one such composition will lie on the solutus line of the Lippmann diagram in equilibrium with a solid whose composition lies on the solidus line and has an activity fraction of BaS04 in the solid solution of X�� S04.…”

Section: (B) Supersaturation In Ss-as Systemsmentioning

confidence: 99%

“…Only relatively recently have there been significant advances in understanding the thermodynamics of such solid-solution -aqueous-solution (SS -AS) systems (Lippmann 1980(Lippmann , 1982Glynn & Reardon 1990). The way in which the supersaturation of a given aqueous solution should be defined, relative to all possible solid-solution compositions, is still contro versial (Prieto et al 1993;Pina et al 2000;Astilleros et al 2002). For the thermo dynamic representation of SS -AS systems, the mixing properties of the solid solution as well as the aqueous solution must be known.…”

Section: Introductionmentioning

confidence: 99%

Nucleation of solid solutions crystallizing from aqueous solutions

Putnis

Pina

Astilleros

et al. 2003

Philosophical Transactions of the Royal Society of London. Seri

View full text Add to dashboard Cite

The study of nucleation and growth mechanisms of salts from aqueous solutions, as a function of supersaturation, is described using both macroscopic and micro scopic experiments. In situ observations in a fluid cell in an atomic force microscope (AFM) reveal phenomena not accounted for in standard crystal-growth theories, specifically on the role of the crystal structure of the substrate in controlling spiral growth and two-dimensional nucleation. As a model example, the crystallization of two isostructural salts, Ba804 and 8r804, is described. The growth of solid-solution crystals is considerably more complex. The supersaturation of a given aqueous solu tion relative to a solid solution is different with respect to each solid composition, and it leads to the possibility that different compositions can simultaneously grow by different mechanisms on the same crystal face. Oscillatory compositional zoning is another consequence of the interplay between the thermodynamics and the kinetics of nucleation. The factors which control nucleation and growth of the solid solution (Ba,8r)804 from an aqueous solution are described. The predictions made from the theory are compared with direct observations of crystal growth in an AFM.

show abstract

“…As an alternative to !3(XCA) function, Astilleros et al (2003c) have recently proposed the following supersat uration b(XBA' XCA) expression, directly derived from the thermodynamic conditions (3a) and (3b): (5) where XclQ is the molar fraction of the solid at equi librium with respect to an aqueous solution of reference which has the same activity fraction as the given aque ous solution. AS equilibrium conditions for b(XBA' XCA) functions) both the maximum supersaturation and the supersatu ration with respect to the end-members are coincident.…”

Section: Equilibrium and Supersaturation In Solid Solution-aqueous Somentioning

confidence: 99%

Nanoscale phenomena during the growth of solid solutions on calcite {101¯4} surfaces

et al. 2006

View full text Add to dashboard Cite

This work deals with the growth behaviour of calcite {I 0 14} surfaces in contact with multicomponent aqueous solutions containing divalent cations (Ba2+, S?+, Mn2+, Cd2+, or Mg2+). The result is the formation of solid solutions, with calcite or aragonite as one of the end-members. In situ atomic force microscopy has revealed a wide variety of surface phenomena occurring during the formation of these solid solutions. Among them are: (l) the thickening of growth steps and the subsequent dissolution of surfaces followed by the nucleation of secondary three-dimensional nuclei on calcite surfaces, (2) the transition between growth mechanisms, (3) the fOlmation of an epitaxial layer that atmours the substrate rrom futiher dissolution and (4) the inhibitory effect of the newly formed surface on the subsequent growth (template effect). The two last phenomena can considerably limit coprecipitation as an effective mechanism for divalent metal uptake. All the phenomena described are a consequence of the interplay between therrnodynamics, supersaturation of the aqueous solution with respect to the possible solid solutions and the crystallographic control of the surfaces on the cation incorporation, and indicates that there are many differences between the crystal growth of solid solutions and phases with fixed composition.

show abstract

Supersaturation functions in binary solid solution–aqueous solution systems

Cited by 47 publications

References 15 publications

Nanoscale growth of solids crystallising from multicomponent aqueous solutions

Nanoscale growth of solids crystallising from multicomponent aqueous solutions

Nucleation of solid solutions crystallizing from aqueous solutions

Nanoscale phenomena during the growth of solid solutions on calcite {101¯4} surfaces

Contact Info

Product

Resources

About