## 3 Results
### Structural Characterization of Metal Titanate Nanorods
The tolerance factor for NiTiO\({}_{3}\), MgTiO\({}_{3}\), and CoTiO\({}_{3}\) is found to be 0.73, 0.75, and 0.76, accordingly. So, because the values below the ilmenite barrier, the samples correspond to ilmenite structure. The tolerance factor for ZnTiO\({}_{3}\) is found to be 0.99 and corresponds to cubic structure. All values are in good agreement with the structural analysis and the theoretical ones. Figure 2: XRD patterns of metal titanate nanorods ATIO\({}_{3}\) (A = Mg, Co, Ni, Zn) after annealing process. It can be seen that no impurity peaks corresponding to the organic impurities were observed. It is known from the literature that vibrations with wavenumbers in the region 830-500 cm\({}^{-1}\) correspond to the formation of metal titanates [61; 62]. More specifically, the peaks at 747 and 535 cm\({}^{-1}\) in MgTiO\({}_{3}\) the peak at 654 cm\({}^{-1}\) for CoTiO\({}_{3}\), the peaks at 723 and 528 cm\({}^{-1}\) for NiTiO\({}_{3}\), and the peaks at 725 and 517 cm\({}^{-1}\) for ZnTiO\({}_{3}\) are attributed to the formation of metal titanates. Furthermore, peaks located below 500 cm\({}^{-1}\) can be assigned to stretching vibrations of M-O bonds where metal denotes the A-site metal in each case or Ti from octahedral TiO\({}_{6}\) groups [63; 64; 65]. These peaks for MgTiO\({}_{3}\) are at 445 and 421 cm\({}^{-1}\), for CoTiO\({}_{3}\) at 489 and 415 cm\({}^{-1}\), for NiTiO\({}_{3}\) at 415 cm\({}^{-1}\), and for ZnTiO\({}_{3}\) at 433 cm\({}^{-1}\). Based on the literature data it is reported that the Raman spectrum of metal titanates has a strong peak at 700 cm\({}^{-1}\) which corresponds to symmetric stretching vibration of MO\({}_{6}\) octahedra, (with M: Mg, Ni, Co, Zn) [66; 67; 68; 69]. All the other signals in MgTiO\({}_{3}\), NiTiO\({}_{3}\), CoTiO\({}_{3}\) can be related to ilmenite Ag, Eg vibrational modes [67]. In ZnTiO\({}_{3}\) all the peaks except the one at 744 cm\({}^{-1}\) are associated with Ag and Eg modes, with the ones at 260 \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Samples**} & \multicolumn{3}{c}{**Lattice Parameters (Å)**} & \multirow{2}{*}{**Volume Cell**} & \multirow{2}{*}{**Crystallite**} & \multirow{2}{*}{**Ionic Radius of**} & \multirow{2}{*}{**Tolerance**} \\  & & **a (a\({}_{\text{th}}\))** & **b (b\({}_{\text{th}}\))** & **c (c\({}_{\text{th}}\))** & & **(Å3)** & **Size (nm)** & **A-Site Metal (Å)** & **Factor** \\ \hline NiTiO\({}_{3}\) & 5.0229 & 5.0229 & 12.9012 & & & & \\  & (5.0312) & (5.0312) & (13.7881) & 976.48 & 19.28 & 0.69 & 0.73 \\ MgTiO\({}_{3}\) & 5.0465 & 5.0465 & 13.8892 & & & & \\  & (5.0548) & (5.0548) & (13.8992) & & & & \\ CoTiO\({}_{3}\) & 5.0579 & 5.0579 & 13.9177 & & & & \\  & (5.0662) & (5.0662) & (13.9180) & & & & \\ ZnTiO\({}_{3}\) & 8.4044 & 8.4044 & 8.4044 & & & & \\  & (8.4080) & (8.4080) & (8.4080) & & & & \\ \hline \end{tabular}
\end{table} 
Table 1: Lattice parameters, volume cell, crystallite size, ionic radius, and tolerance factor of metal titanate nanorods ATIO\({}_{3}\) (A = Mg, Co, Ni, Zn). Figure 3: FT-IR spectra of metal titanate nanorods ATIO\({}_{3}\) (A = Mg, Co, Ni, Zn) after annealing process. and 440 cm\({}^{-1}\) being associated to octahedral TiO\({}_{6}\) group [39]. Raman spectrum of metal titanates are shown in Figure 4.