Infrared and Raman spectroscopic characterization of the phosphate mineral kosnarite KZr2(PO4)3 in comparison with other pegmatitic phosphates

• Published in: Transition metal chemistry (Weinheim) Vol. 37; no. 8; pp. 777 - 782
• Main Authors: Frost, Ray L., Xi, Yunfei, Scholz, Ricardo, Belotti, Fernanda M.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.11.2012
• Subjects: Catalysis; Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Organometallic Chemistry; Physical Chemistry; Raman Spectrum; Raman Band; Uranium Deposit; Phosphate Anion; Zirconium Phosphate
• ISSN: 0340-4285; 1572-901X
• DOI: 10.1007/s11243-012-9652-x

In this research, we have used vibrational spectroscopy to study the phosphate mineral kosnarite KZr 2 (PO 4 ) 3 . Interest in this mineral rests with the ability of zirconium phosphates (ZP) to lock in radioactive elements. ZP have the capacity to concentrate and immobilize the actinide fraction of radioactive phases in homogeneous zirconium phosphate phases. The Raman spectrum of kosnarite is characterized by a very intense band at 1,026 cm −1 assigned to the symmetric stretching vibration of the PO 4 3− ν 1 symmetric stretching vibration. The series of bands at 561, 595 and 638 cm −1 are assigned to the ν 4 out-of-plane bending modes of the PO 4 3− units. The intense band at 437 cm −1 with other bands of lower wavenumber at 387, 405 and 421 cm −1 is assigned to the ν 2 in-plane bending modes of the PO 4 3− units. The number of bands in the antisymmetric stretching region supports the concept that the symmetry of the phosphate anion in the kosnarite structure is preserved. The width of the infrared spectral profile and its complexity in contrast to the well-resolved Raman spectrum show that the pegmatitic phosphates are better studied with Raman spectroscopy.