Thermodynamics, cluster formation and crystal growth in highly supersaturated solutions of KDP, ADP and TGS

Bohenek, M.; Myerson, Allan S.; Sun, Wei

doi:10.1016/s0022-0248(97)00121-8

Cited by 31 publications

(38 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…7B). We note that spinodal decomposition has been predicted in KDP solutions under extremely supersaturated condition, at about S ∼ 25.56 (30), in which solution density is higher than that of the crystal. Because the supersaturation in our current study is far below the spinodal line, this topic requires further studies.…”

mentioning

confidence: 64%

“…Motivated by these questions and technical challenges, we have developed an instrument that integrates a containerless device based on the electrostatic levitation (ESL) with in situ micro-Raman and X-ray scattering apparatus. Although there have been previous efforts to combine levitation techniques [acoustic (27,28) and electrodynamic levitation (29,30)], various technical limitations such as the presence of strong acoustic pressures or very small sample sizes may have hindered direct observation of the spontaneous nucleation at the deepest level of supersaturation.…”

Section: Significancementioning

confidence: 99%

See 1 more Smart Citation

Multiple pathways of crystal nucleation in an extremely supersaturated aqueous potassium dihydrogen phosphate (KDP) solution droplet

Lee

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Solution studies have proposed that crystal nucleation can take more complex pathways than previously expected in classical nucleation theory, such as formation of prenucleation clusters or densified amorphous/liquid phases. These findings show that it is possible to separate fluctuations in the different order parameters governing crystal nucleation, that is, density and structure. However, a direct observation of the multipathways from aqueous solutions remains a great challenge because heterogeneous nucleation sites, such as container walls, can prevent these paths. Here, we demonstrate the existence of multiple pathways of nucleation in highly supersaturated aqueous KH 2 PO 4 (KDP) solution using the combination of a containerless device (electrostatic levitation), and in situ micro-Raman and synchrotron X-ray scattering. Specifically, we find that, at an unprecedentedly deep level of supersaturation, a highconcentration KDP solution first transforms into a metastable crystal before reaching stability at room temperature. However, a low-concentration solution, with different local structures, directly transforms into the stable crystal phase. These apparent multiple pathways of crystallization depend on the degree of supersaturation.multipath nucleation | liquid-droplet levitation | supersaturation | in situ X-ray diffraction | in situ micro-Raman spectroscopy N ucleation is the first step toward crystallization, in which atoms or particles aggregate to form clusters in a metastable liquid, called crystal nuclei. The crystal nuclei in metastable liquid grow continuously if their size exceeds a critical limit, and are subsequently stabilized. Based on the classical nucleation theory (CNT) (1, 2), nucleation is mainly governed by two factors, that is, interfacial free energy and volume Gibbs free energy (or chemical potential) between liquid and crystal phases. Although the volume Gibbs free energy acts to stabilize the crystal nuclei, the interfacial free energy works as an energy barrier preventing the formation of the nuclei. If the crystal-liquid interfacial free energy creates a sufficiently high energy barrier, the liquid can be supercooled, supersaturated, or even supercompressed. In case of liquid metals (3-6), the crystal-liquid interfacial free energy arises from configurational entropy differences between crystal and liquid. That is, the greater difference in local structural orderings between crystal and liquid phases results in higher interfacial free energy, which consequently leads to a higher nucleation barrier and thus deeper supercooling. This concept has been verified in various metallic systems for elements (7) and many alloys (8-12). However, many experimental and theoretical investigations have raised questions that CNT may not be adequate to describe the initial nucleation processes in biomaterials (13-17) and minerals (18)(19)(20)(21)(22)(23)(24)(25)(26).Recently, an alternate nucleation mechanism, called multipathway nucleation (or crystallization) (13-23, 25, 26), has been proposed fo...

show abstract

mentioning

confidence: 64%

Section: Significancementioning

confidence: 99%

Multiple pathways of crystal nucleation in an extremely supersaturated aqueous potassium dihydrogen phosphate (KDP) solution droplet

Lee

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…The same can be said for solutions of alkali mental and ammonium nitrates [17]. Formation of clusters is an acknowledged experimental fact that was found in solutions of various substances including NiCl 3 [18], KDP, ADP, TGS [19], and NaNO 3 [20,21]. There are some proofs of formation of nano-sized "islands" of liquid-crystal electrolyte hydrate in concentrated solutions [22].…”

Section: Resultsmentioning

confidence: 99%

Temperature‐concentration oscillations of crystal‐solution phase equilibria in the presence of trace impurities of surface‐active agents

Kir'yanova

2011

Cryst. Res. Technol.

View full text Add to dashboard Cite

Using the examples of aqueous salt solutions NaNO 3 , KNO 3 , RbNO 3 , K 2 SO 4 , NaBr . 2Н 2 О, KBr, and NН 4 NO 3 , it was experimentally proven that the new phenomena, i.e. temperature-concentration oscillations of crystal-solution phase equilibria detected previously in the range of 15-45 °С remain in the presence of trace impurities (10 -4 -10 -3 wt. %) of ion-active organic matters. The signs of breaks transformation into pair oscillations of "maximum-minimum" type are established for the K 2 SO 4 , NaBr, KBr solutions. The efficiency of influence of trace impurities on phase equilibria sharply rises in the areas of the temperature-concentration oscillations (the saturation temperature ranges up to 10 K). The impurity efficiency is promoted by the presence of the amides in its content (as compared with the sulphates) and an increase in length of the hydrocarbon radical. The phenomenon is absent in case of an addition of ion-inactive compounds.

show abstract

“…Models for crystal growth are usually explained in terms of growth units, diffusion and interface kinetics processes. The kinetics of interface incorporation is far more complicated than the kinetics of diffusion, being a function of crystal face, impurity concentration and other factors [1]. Therefore, the interface physics of crystal growth is still not well understood.…”

Section: Introductionmentioning

confidence: 99%

“…As shown by recent literature [1,3], its use in crystal growth research quickly increases, mainly owing to its capability to reveal the formation of ion pairs and higher-order clusters in solid-liquid interface boundary layers. Furthermore, Raman measurement does not damage the interface structure and can be used for in situ inspection of the kinetic processes within the interface boundary layer.…”

Section: Introductionmentioning

confidence: 99%

Cluster Formation in Solid-Liquid Interface Boundary Layers of KDP Studied by Raman Spectroscopy

Xia

Sun

et al. 2001

phys. stat. sol. (a)

View full text Add to dashboard Cite

The cluster formations in solid-liquid interface boundary layers of KDP crystals have been studied by Raman spectroscopy and ab initio cluster calculations with the density-functional theory. The calculations are made on H 2 PO 4 , H 4 P 2 O 8 , and H 4 P 4 O 16 clusters, which model the cluster structure in different growth layers. Excellent agreement has been achieved between vibrational frequencies predicted by theory and those observed in experiments. The present results also show that the desolvation process of polymer clusters takes place within the characteristic boundary layers. The growth unit of crystal growth is identified as H 4 P 2 O 8 dimer cluster.

show abstract

Thermodynamics, cluster formation and crystal growth in highly supersaturated solutions of KDP, ADP and TGS

Cited by 31 publications

References 26 publications

Multiple pathways of crystal nucleation in an extremely supersaturated aqueous potassium dihydrogen phosphate (KDP) solution droplet

Multiple pathways of crystal nucleation in an extremely supersaturated aqueous potassium dihydrogen phosphate (KDP) solution droplet

Temperature‐concentration oscillations of crystal‐solution phase equilibria in the presence of trace impurities of surface‐active agents

Cluster Formation in Solid-Liquid Interface Boundary Layers of KDP Studied by Raman Spectroscopy

Contact Info

Product

Resources

About