CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

peaks are found to decrease with increase in ethylene glycol content in the reaction medium.
Table 7 shows the variation in average crystallite size as a function of relative amounts of
ethylene glycol and glycerol in the reaction medium. From these results, it is inferred that the
average crystallite size can be tuned by varying the relative amounts of ethylene glycol and
glycerol in the reaction medium. The observed variation in the crystallite size with change in
the relative concentration of the solvent has been explained based on the increase in viscosity
of the medium with increase in the relative concentration of glycerol and associated increase
in growth rate. XRD patterns are least square fitted to determine the lattice parameters. The
values for un-doped SbPO 4 samples are a = 5.099(1) Å, b = 6.767(2) Å, c = 4.749(1) Å with β
= 94.73. Corresponding values for the 5% Tb 3+ doped nanoparticles are a = 5.093(1) Å, b =
6.769(2) Å, c = 4.733(1) Å with β = 94.69. There is no significant change in the values of
lattice parameters for both doped and un-doped samples. This can be attributed to the
comparable ionic radii of Sb 3+ and Tb 3+ under a coordination number of four. In order to
check the nature of amorphous product obtained when pure ethylene glycol is used as the
solvent, IR patterns were recorded for the amorphous product and it is compared with the
patterns obtained from crystalline SbPO 4 sample. Figure 62 shows IR spectra of as prepared
SbPO 4 sample obtained by using pure ethylene glycol, pure glycerol and a mixture of
glycerol and ethylene glycol (10 ml each).
Table.7. Effect of variation volume of solvents on the average crystallite size of SbPO 4
nanomaterials.
Volume of
glycerol (ml)
Volume of ethylene
glycol (ml)
Average crystallite size
(nm)
20 0 46
10 10 28
8 12 12
0 20 -
114