Redox Reactions in Strontium Iron Phosphates: Synthesis, Structures, and Characterization of Sr₉Fe(PO₄)₇ and Sr₉FeD(PO₄)₇.

Abstract

Iron I 7100Redox Reactions in Strontium Iron Phosphates: Synthesis, Structures, and Characterization of Sr9Fe(PO4)7 and Sr9FeD(PO4)7. -Sr9Fe(PO4)7 (I) is prepared from a mixture of SrCO3, Fe2O3, and NH4H2PO4 (1370 K, 120 h). Sr9FeD(PO4)7 (II) is synthesized by treating (I) with 20% D2/Ar at 820 K (48 h). The compounds are characterized by Moessbauer, IR, and Raman spectroscopy, magnetization and dielectric measurements, differential scanning calorimetry, and thermal analysis. (I) undergoes an antiferroelectric-paraelectric phase transition at 740 K. It crystallizes in the space group C2/c with Z = 4 at room temperature (powder neutron diffraction) and in space group R3m with Z = 3 at 923 K (powder XRD). Compound (II) is isotypic with the paraelectric phase of (I), i.e. it crystallizes in the space group R3m with Z = 3 at 293 K. -(BELIK*, A. A.; IZUMI, F.; AZUMA, M.; KAMIYAMA, T.; OIKAWA, K.; POKHOLOK, K. V.; LAZORYAK, B. I.; TAKANO, M.; Chem. Mater. 17 (2005) 22, 5455-5464; Adv. Mater. Lab., Int. Cent. Young Sci., Natl. Inst. Mater. Sci., Ibaraki, Tsukuba 305, Japan; Eng.) -W. Pewestorf 03-023

Luminescence Enhancement of Red‐Emitting Sr9MnK(PO4)7 Phosphor via Energy Transfer and Charge Compensation

“…51-0427). [17] Obviously, the SMKP compound is isostructural to Sr 9 Fe 1.5 (PO 4 ) 7 . All the phosphors are in a single-phase state, revealing that Eu 2þ or Ce 3þ ions are incorporated into the SMKP host lattice.…”