The synthesis and thermal stability of CaKCe(PO4)2 phosphate. Phase equilibria in the CaKPO4–CePO4 system

Structural and Luminescence Behavior of Nanocrystalline Orthophosphate KMeY(PO4)2: Eu3+ (Me = Ca, Sr) Synthesized by Hydrothermal Method

“…Three of them, Γ T = A 2 + E 1 (3), describe the acoustic phonons, and the remainder, Γ O = 3A 1 + 4A 2 + 5B 1 + 5B 2 + 9E 1 + 8E 2 (51), correspond to the optical modes. The optical modes can be further subdivided by the vibrations of the respective components of the primitive cell, i.e., translations of Ca 2+ /Y 3+ ions: (27), as well as translations and librations of the PO 4 3− ions, Γ T/L (PO 4 ) = A 2 + B 1 + B 2 + 2E 1 + E 2 (6). In the discussion of the IR and Raman spectra, the correlation between the molecular T d , site D 2 , and factor D 6 symmetry should be used.…”

“…Samples doped with Ce 3+ , Tb 3+ , and Mn 2+ exhibited high quantum efficiency (60%) and were obtained by a Pechini method [22]. Compounds are mostly obtained via a conventional ceramic method (sintering at high temperatures), however, results presented in [25][26][27] show that obtaining single-phase KMeRE(PO 4 ) 2 is difficult because of the limited thermal stability of such ternary phosphates at temperatures exceeding 1100-1200 • C. A relatively mild hydrothermal process (short-term heating carried out at 240 • C) has been applied for the synthesis of phase-pure KCaCe(PO 4 ) 2 , which resulted in obtaining nanocrystalline powders [27].…”