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Figure 7.65 Schematic diagrams of the variation in morphology of superionic
pyrophosphates with P
2
O
5
content in the system.
of
Figure 7.65
. As the concentration of P
2
O
5
and H
2
O increases, the pyramidal
faces are replaced by the prismatic and the pinacoidal faces
[298]
. Similarly, an
attempt has been made to study the variation of the growth rate of NaHCo(P
2
O
7
)
crystals with concentration of P
2
O
5
,Na
2
O, and H
2
O(
Figure 7.66a
c
). These
figures show critical points, beyond which the growth rate falls sharply. This helps
to fix the optimum conditions for the growth of NaHCo(P
2
O
7
)
[298]
.
Similar features were observed in the case of NaHZn(P
2
O
7
) ry .
Representative photographs (
Figure 7.67
)ofNaHZn(P
2
O
7
) show how morphology
