Raman spectroscopic study of the phase transitions sequence in Li3Fe2(PO4)3 and Na3Fe2(PO4)3 at high temperature

Synthesis, crystal structure and infrared spectroscopy of a new non-centrosymmetric mixed-anion phosphate Na4Mg3(PO4)2(P2O7)

“…2) running parallel to the c axis. The Na(1) and Na (4) atoms are placed at the intersection of B2 and C1 and B1 and C1, respectively. The Na(2) and Na (3) (1), Na(2), Na(3) and Na(4), respectively.…”

“…PO 4 3− vibrations The internal vibrational modes of a free PO 4 3− tetrahedron with T d symmetry are decomposed as A 1 + E + 2T 2 . The mode with the A 1 symmetry type is the symmetric stretching mode ( 1 ) of the P-O bonds.…”

“…The second mode with the T 2 symmetry is the asymmetric stretching mode ( 3 ). For a free PO 4 3− tetrahedron, 1 = 938 cm −1 , 2 = 420 cm −1 , 3 = 1017 cm −1 , and 4 = 567 cm −1 .…”

“…Inorganic phosphates encompass a large class of diverse materials with numerous important industrial uses, e.g., as catalysts, ion-exchange materials, solid electrolytes for batteries, as linear and non-linear optical components, chelating agents, in synthetic replacements for bone and teeth, and as phosphors, detergents and fertilizers [1][2][3][4][5][6][7][8][9][10]. Inorganic phosphates may represent perhaps one of the most interesting types of new inorganic materials, in large part, due to the ability of the tetrahedral PO 4 3− group to bond with other structural units.…”

“…Inorganic phosphates may represent perhaps one of the most interesting types of new inorganic materials, in large part, due to the ability of the tetrahedral PO 4 3− group to bond with other structural units. The studies of the phosphates Na 4 M II 3 (PO 4 ) 2 (P 2 O 7 ) (M = Mn, Co, Ni) [11][12] and Na 4 Ni 5 (PO 4 ) 2 (P 2 O 7 ) 2 [13] showed a quite unusual disordered distribution of the P 2 O 7 groups in the mixed frameworks of this series of isostructural compounds.…”