Geoscience Reference
In-Depth Information
4
Physical Chemistry of Hydrothermal
Growth of Crystals
4.1 Introduction
This is perhaps the least known aspect of the hydrothermal growth of crystals.
No topic on crystal growth gives a complete picture of the theoretical aspects of
hydrothermal growth. Similarly, no author has produced a definitive discussion of
the physical chemistry of hydrothermal growth of crystals, covering aspects of physico-
chemical and hydrodynamic principles, solutions, solubility, phase equilibria,
thermodynamics, kinetics, modeling or intelligent engineering of the hydrothermal
reactions, and so on. The Nobel Symposium organized by the Royal Swedish
Academy of Sciences during 1978, followed by the First International Symposium
on Hydrothermal Reactions organized by the Tokyo Institute of Technology in
1982, helped in setting a new trend in hydrothermal technology by attracting physi-
cal chemists in large numbers
[1,2]
. Hydrothermal physical chemistry today has
enriched our knowledge greatly through a proper understanding of hydrothermal
solution chemistry, which holds a key to the intelligent engineering of materials.
This is also popularly known as thermochemical modeling or thermochemical com-
putation. There are several groups all over the world working on various aspects of
physical chemistry under hydrothermal conditions.
4.1.1 Physicochemical and Hydrodynamic Principles of the
Hydrothermal Growth of Crystals
This is one of the fundamental aspects of hydrothermal growth of crystals. There
are two aspects to be discussed here:
i. The physicochemical studies on various aqueous solutions studied within a wide range of
pressure
temperature conditions.
ii. The physical chemistry of the hydrothermal growth of crystals.
Each one of these has been studied extensively. However, the correlation of the
two works has not been done with enough accuracy.
Ezersky et al.
[3,4]
have studied the hydrodynamics under hydrothermal condi-
tions using a shadowgraph technique. This facilitated understanding of the spatio-
temporal structure of hydrothermal waves in Marangoni convection. However, a lot
more experimental and theoretical developments are needed to clarify and complete
