Non-random cation distribution in hexagonal Al0.5Ga0.5PO4

✍ Scribed by S.K. Kulshreshtha; O.D. Jayakumar; V. Sudarsan

• Book ID: 104030618
• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 244 KB
• Volume: 183
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2010.03.010

✦ Synopsis

Based on powder X-ray diffraction and 31 P Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) investigations of mixed phosphate Al 0.5 Ga 0.5 PO 4 , prepared by co-precipitation method followed by annealing at 900 1C for 24 h, it is shown that Al 0.5 Ga 0.5 PO 4 phase crystallizes in hexagonal form with lattice parameter a ¼0.491(2) and c ¼1.106(4) nm. This hexagonal phase of Al 0.5 Ga 0.5 PO 4 is similar to that of pure GaPO 4 . The 31 P MAS NMR spectrum of the mixed phosphate sample consists of five peaks with systematic variation of their chemical shift values and is arising due to existence of P structural units having varying number of the Al 3 + /Ga 3 + cations as the next nearest neighbors in the solid solution. Based on the intensity analysis of the component NMR spectra of Al 0.5 Ga 0.5 PO 4 , it is inferred that the distribution of Al 3 + and Ga 3 + cations is non-random for the hexagonal Al 0.5 Ga 0.5 PO 4 sample although XRD patterns showed a well-defined solid solution formation.