Crystal chemistry of (RE, A)₂M₃O₇ compounds (RE=Y, lanthanide; A=Ba, Sr, Ca; M=Al, Ga)

Abstract

Phases of general formula (RE,A) 2 M 3 O 7 (RE=lanthanide, A=Ca, Sr, Ba; M=Ga, Al) are of interest for their nonlinear optical properties and have potential as solid state lasers. Their structures have been refined using X-ray and neutron diffraction data and are related to gehlenite, Ca 2 Al 2 SiO 7 , with M cations occupying Al and Si sites and RE and A cations sharing the Ca site with no evidence for ordering, although they occur in the ratio 1:1 because of stoichiometry; the M cations are tetrahedrally coordinated. (RE,Ba) 2 M 3 O 7 compounds cannot be synthesized for M=A1 or for RE cations smaller than Sm; this limitation is believed to be due to size mismatch between cations within the structure. © 1999 International Centre for Diffraction Data. [S0885-7156(99)00501-l]

Blue emission properties of Eu-doped CaAl2O4 phosphors synthesized by a flux method

“…A CA single phase was observed up to 2 mol% Eu 2+ , while EuCaAl 3 O 7 secondary phase appeared at 6 mol% Eu 2+ and gradually increased by adding more Eu 2+ ions. It was reported that EuCaAl 3 O 7 could be formed by the reaction of calcium mono aluminate and europium aluminate by solid-state reaction at 1300-1400 • C [17]. In this experiment, europium concentrations PL intensity (Fig.…”

Layered LaSrGa3O7‐Based Oxide‐Ion Conductors: Cooperative Transport Mechanisms and Flexible Structures

“…The experimental crystal structures of the stoichiometric parent compound [22] and the oxygen excess [13] compound were used as the initial structures for modeling. Interatomic potentials and shell model parameters were transferred from previous work, [12,23] Table 1.…”

Synthesis, growth, and characterization of Nd-doped SrGdGa3O7 crystal

“…1. 16 According to the peak 2 values in the XRPD pattern, the tetragonal unit cell parameters are calculated to be a = b = 7.972 Å, c = 5.251 Å. The structure of the as-grown crystal was studied by x-ray powder diffraction ͑XRPD͒, and results are shown in Fig.…”