Oxide ion conductive structure and chemical stability of Nd2Gd2O3F6

Revised crystal structure and luminescent properties of gadolinium oxyfluoride Gd4O3F6doped with Eu3+ions

“…In the presented studies, concerning mainly the ionic conductivity of oxyfluorides, a monoclinic crystal system of the P2/c space group is reported. [26][27][28][29][30][31] The assignment of a tetragonal structure to binary rare earth oxyfluorides results in a discrepancy in the positions of XRD reflections with the reference pattern. Also the shape of XRD peaks recorded, their intensity and the ratio between them are in disagreement with the theoretical pattern.…”

Crystal chemistry and electrical conductivity of Ln2Eu2O3F6 (Ln: Nd, La)

“…Because binary rare-earth oxide fluorides exhibit oxide ion conduction, the structural aspects resulting in the oxide ion conduction have been considered as the background information to simulate the crystal structure. The stoichiometric compounds, Nd 2 Ln 2 O 3 F 6 were analyzed by relating to the known structures of simple rare-earth oxide fluorides, such as the tetragonal Nd 4 O 3 F 6 [7,10,11]. The crystal structure analyses of some Nd 2 Ln 2 O 3 F 6 (Ln = Ce, Eu, Sm, Gd) compounds with much higher oxide ion conductivity were already finished and their lattice parameters were registered in the powder diffraction file [14].…”

“…Ln 2 Eu 2 O 3 F 6 (Ln: Nd, La) are obtained by the solid-state reaction between Ln 2 O 3 (Ln: Nd, La) and EuF 3 at a temperature higher than 1000 • C [8][9][10][11] perature higher than 700 • C, all the preparative operations, such as powdering, mixing and firing must be performed in a highly dried atmosphere in addition to sufficient dehydration of starting materials. The compositions of products were analyzed by X-ray fluorescence spectroscopy (Shimadzu: SXF-1100s).…”

“…Density was measured by using a helium gas displacement pycnometer (Micromeritics: AccPyc-1330). The X-ray diffraction results were analyzed by computational methods using RIETAN programs [10,11]. The disc samples (13φ × 2 mm) for the electrical conductivity measurements were prepared by hot pressing at a temperature from 1000 to 1200 • C under 20 MPa in argon.…”

“…The disc samples (13φ × 2 mm) for the electrical conductivity measurements were prepared by hot pressing at a temperature from 1000 to 1200 • C under 20 MPa in argon. The electrical conductivity has been examined by ac method (EG&G Instruments: Potentiostat 283vs and FRA1120, 3-10 MHz) at a temperature between 400 and 700 • C under a partial pressure of oxygen ranging from 1 × 10 −2 to 2 × 10 4 Pa [9][10][11][12]. The oxide ion transport number was examined by the EMF method using an oxygen gas concentration cell, and the charge-carrying species in Ln 2 Eu 2 O 3 F 6 was examined by an electrolysis method [12] and a dc polarization method [13].…”