Structures of two new high-pressure forms of AlPO4 by X-ray powder diffraction and NMR spectroscopy.

The crystal structures of two new high-pressure AlPO(4) phases are reported. One phase synthesized at 6 GPa and 1523 K is triclinic (P1) whilst the other phase synthesized at 7 GPa and 1773 K is monoclinic (P2(1)/c). (31)P MAS (magic-angle spinning) NMR suggests three tetrahedral P sites with equal abundance in both phases.

Enhanced photoluminescence from mixed-valence Eu-doped nanocrystalline silicate glass ceramics.

Intense photoluminescence was observed from mixed-valence Eu-doped nanocrystalline BaAl₂Si₂O₈/LaBO₃ glass ceramics. For preparation in air, the ratio between Eu3+ and Eu2+ luminescence depends on synthesis temperature. XRD, TEM and IR absorption spectra were employed to characterize the crystallization process and structural properties of the precursor glass and corresponding glass ceramics.