Etude de la structure K2NiF4 par la méthode des invariants, I. Cas des oxydes A2BO4

The phase diagram and crystal chemistry of strontium-doped rare earth cobaltates: Ln2−xSrxCoO4+δ (Ln=La–Dy)

“…A guide can be taken from tolerance factor values (0.85 < t < 1.05) as to whether K 2 NiF 4 -type structures will be formed [26]. Based on tabulated values of ionic radii for rare earth ions, Sr 2+ , Co 2+ , Co 3+ , and Co 4+ [27], one can calculate t for these Ln 2−x Sr x CoO 4 phases.…”

Effect of the Anisotropy Field and Magnetic Ordering on the Electrical Properties of Substituted and Unsubstituted Nd2CuO4

“…where r(R±O) and r(Cu±O) are the sums of the ionic radii for R or Cu cations and the oxygen ion [14]. 2.…”

Solid state chemistry of Ruddlesden-Popper type complex oxides

“…NdtxsCe0.~sCuO 4 (T=24K) and Nd2CuO36F0.4 (T c = 27 K) are examples of this category of superconductors (James et al 1989;Tokura et al 1989). La ÷tNiO3,+~ (n= I, 2 and 3) series is one of the widely studied systems (Poix 1980;Drenan et . The crystal structure of LaaNiO 4 is reported to be tetragonal with space group 14/mmm; electron diffraction studies, however, show it having monoclinic distortion.…”

“…According to the literature survey, of all the known compounds, hardly 5% have rA/r B values lying outside the prescribed range. By using invariant method, Poix (1980) has given the following relation between the average cation-oxygen distances associated to the 9 and 6 coordinated sites (VA and fiB) and volume V of the unit cell in I~NiF 4 structure: 0-99615 V 113 =~B "1-VA 21/2" K2NiFa-type structure is two-dimensional in the sense that only equatorial anions of BO 6 octahedra are linked through the corners. The perovskite and K2NiF4-type structures are shown in figure 1.…”