Effective ionic radii in oxides and fluorides

Abstract

KAREN GRAM JENSEN AND BODIL JERSLEV 925 structure is viewed along the b axis. This projection illustrates very clearly that the external shape of a crystal -in this case the prominence of {10T} -is a function of the packing of the molecules in the crystal lattice.We are indebted to Professor R. W. Asmussen, Chemical Laboratory B, Technical University of Denmark for his kind interest and support during the final stages of this research.

Oxygen-vacancy ordering in lanthanide-doped ceria: Dopant-type dependence and structure model

“…10, the data for Y-doped ceria are also displayed for comparison, of which Y has a quite different electronic configuration from those of lanthanides ͑Y 3+ : ͓Kr͔4d 0 ; Ln 3+ : ͓Xe͔4f n , n =0-14͒. Probably because of this, a deviation of this material from the linear correlation belonging to Ln-doped ceria can be readily seen though the radius of Y 3+ cation 34 and the value of ⌬a are similar to those of the lanthanides.…”

Dynamic Stereochemical Activity of the Sn2+ Lone Pair in Perovskite CsSnBr3

“…Ca 2+ is chosen for comparison because of its identical ionic radius to Sn 2+ in octahedral coordination, as calculated from bond valence sums in oxides. 77,78 Because effective ionic size depends on the ligands, CsSnBr (200) is presented in Figure 8(b), for the case where Sn 2+ is displaced along [111]. An asymmetric lobe of elevated localization opposite to the direction of cation dis-placement is indicative of the broken inversion symmetry of the lone pair that has become stereochemically active.…”

Tl4Ge4Se10, ein Thallium(1)selenogermanat mit adamantananalogem Anion [Ge4Se10]4- / Tl4Ge4Se10, a Thallium(I) Selenogermanate with the Adamantane-Like Anion [Ge4Se10]4-

“…Im TlInSe2 [13] ist das Tl-Atom von acht Se-Atomen in quadratischantiprismatischer Anordnung (Tl-Se: 3,448 Ä), im TlGaSe2 [14] in gleicher, jedoch stärker verzerrter Konfiguration ebenfalls von acht Se-Atomen umgeben (mittlerer Abstand Tl-Se: 3,515 Ä). Ein Vergleich mit der Summe der entsprechenden Ionenradien erscheint wegen der unterschiedlichen Literaturwerte für den Radius von T1+ [11,15] …”