44
L. Badr, R. Sultan / Chemical Physics Letters 453 (2008) 40–44
ꢁ
spatial distribution and temporal evolution come to com-
plete the picture and support the underlying dynamical
scenario.
AlðOHÞ =AlðOHÞ [29] systems. Thus, the above studies
3
4
provide sources of a wealth of exotic behaviors, with par-
ticularly rich and diverse dynamics, that continue to stim-
ulate experimental and theoretical research on this
fascinating phenomenon.
The mathematical formulation of the reaction–diffu-
sion–redissolution processes [6] in accordance with the
model of M u¨ ller and Polezhaev [16] modifed by Al-Ghoul
and Sultan [12] captures the essential features of the
dynamics in this two-precipitate system. The model com-
bines both nucleation and kinetics of particle growth, cou-
pled to diffusion. The conjecture of precipitate composition
proportions within the bands are congruent with the com-
plex ion dynamical evolution reported in the present work,
notably the preferential redissolution of Ni(OH)2 over
Acknowledgements
This work was supported by a University Research
Board (URB) grant (American University of Beirut). All
spectrophotmetric measurements were performed in the
Central Research Science Lab (CRSL) of the Faculty of
Arts and Sciences.
Co(OH) . The latter is due to the more favored formation
2
2
6
þ
2þ
3
of NiðNH Þ over CoðNH Þ . Other theoretical frame-
3
6
References
works based on the model of B u¨ ki et al. [17] treat the Liese-
gang problem in the presence of complex formation
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37 (1896) 305, continued in 37, 331.
[
18–20], but deal only with single-salt schemes. Whereas
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þ
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4
[
[
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[
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´
[
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[29] A. Volford, F. Izs a´ k, M. Ripsz a´ m, I. Lagzi, J. Phys. Chem. B 110
2ꢁ
tion patterns with redissolution feature the HgI =HgI
2
4
ꢁ
(
2006) 4535.
[
23–25], the CrðOHÞ =CrðOHÞ4 [26–28] and the
3