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Tb 3 Pd 2 , Er 3 Pd 2 and Er 6 Co 5– x : structural variations and bonding in rare‐earth‐richer binary intermetallics
Author(s) -
Bell Thomas,
Celania Chris R.,
Smetana Volodymyr,
Mudring Anja-Verena,
Meyer Gerd
Publication year - 2018
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229618010549
Subject(s) - crystallography , transition metal , structure type , stoichiometry , type (biology) , tin , crystal structure , space group , rare earth , chemistry , metal , electronic structure , materials science , x ray crystallography , physics , computational chemistry , mineralogy , metallurgy , diffraction , biochemistry , catalysis , ecology , biology , optics
The three binary Tb/Er‐rich transition metal compounds Tb 3 Pd 2 (triterbium dipalladium), Er 3 Pd 2 (trierbium dipalladium) and Er 6 Co 5– x (hexaerbium pentacobalt) crystallize in the space groups Pbam (Pearson symbol oP 20), P 4/ mbm ( tP 10) and P 6 3 / m ( hP 22), respectively. Single crystals of Tb 3 Pd 2 and Er 6 Co 5– x suitable for X‐ray structure analysis were obtained using rare‐earth halides as a flux. Tb 3 Pd 2 adopts its own structure type, which can be described as a superstructural derivative of the U 3 Si 2 type, which is the type adopted by Er 3 Pd 2 . Compound Er 6 Co 5– x belongs to the Ce 6 Co 2– x Si 3 family. All three compounds feature fused tricapped { TR 6 } ( R = rare‐earth metal and T = transition metal) trigonal prismatic heterometallic clusters. R 3 Pd 2 is reported to crystallize in the U 3 Si 2 type; however, our more detailed structure analysis reveals that deviations occur with heavier R elements. Similarly, Er 6 Co 5– x was assumed to be stoichiometric Er 4 Co 3 = Er 6 Co 4.5 . Our studies reveal that it has a single defective transition‐metal site leading to the composition Er 6 Co 4.72(2) . LMTO (linear muffin‐tin orbital)‐based electronic structure calculations suggest the strong domination of heteroatomic bonding in all three structures.