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Chapter II Solution Growth….
104
(2.19)
Where, v is the molar volume of the crystal, N is the Avagadro’s
number and R is the gas constant. Equation (2.19) suggests a straight line for
a plot of
2
1/ 1n S against 1n can be drawn with a slope given by,
3 2
16
N
m
3 3
(2.20)
3R T
Since B weakly depends on temperature. All the quantities in equation
(2.20) are known except the interfacial tension . The interfacial tension of the
solid relative to its solution can be calculated from the slope of the line 1/lnS 2
as,
(2.21)
The energy of formation of a critical nucleus can be calculated from the
experimental using following relation,
(2.22)
The radius of the nucleus in equilibrium with its solution has been
computed as,
2.24 Effect of Soluble Impurities on Nucleation
(2.23)
The nucleation rate of a solution or melt can be affected appreciably
by the presence of mere traces of impurities in the system. Crystallization
from solutions always proceeds in multi component systems, because even
in the purest form there are some impurities. Impurities may be both in