Crystal structure of erbium palladium phosphor (3:20:6), Er3Pd20P6

Abstract

Source of materialErbium, red phosphorus, and palladium were of 99.99 wt.-% purity. Amixture of the starting components with nominal composition Er 3 Pd 20 P 6 was pressed into asmall pellet (1 g) and melted in an arc furnace under aTi/Zr-gettered argon atmosphere at normal pressure. The alloy was heat-treated at 1070 Kfor 20 dinevacuated fused silica ampules, followed by quenching in cold water. After the sample was crushed, bar-likeair-stable single crystals with metallic luster were extracted and were for the structure determination. Energy-dispersive analysis of several crystals in a scanning electron microscope confirmed the presence of erbium, palladium,and phosphorus as the only components in atomic percentages of Er:Pd:P=11:68:21 (with estimated standard deviations of 2%). DiscussionEr 3 Pd 20P 6 adopts the Cr 23C 6 -type structure (Pearson symbol cF116) [1], which is built up of fragments of columnsofcuboctahedra ( figure, top), two tetragonal antiprisms, and cubes (figure, middle). The Eratoms substitute for the transition metals in sites 4 a and 8 c .The Patoms have tetragonal antiprismatic coordination ( figure, bottom). The shortesti nteratomic distance found ( d (Pd1-P)=235.6(2) pm) is by <5%smaller than the sumof atomic radii. Because of the low rare-earth content, the Eratoms remain isolated, and interatomic distances to them are larger than the sum of atomic radii. The greatest contraction (9.4 %) occurs for the Er2-Pd2 distance of 281.95(5)p m, indicating that the bonding between Erand Pdatoms is probably stronger than that between Pdand P,orErand P.Er 3 Pd 20 P 6 is paramagnetic and its susceptibility followsthe Curie-Weiss law.

Chemical Flexibility of Mg in Pnictide Materials: Structure and Properties Diversity

“…RE3Pd20Pn6 [43] Sn2NiNi20P6, [44] In2NiNi20P6 [45] Mn3TM20P6 [42] MgNi3P [37] [hex. Mg2Cu] RETM3Tt [46] (Mg0.5Ge0.5)P [47] [ZnS]…”

“…The Ni-P framework in the crystal structure of M3Ni20P6 (M = Mg, Mn, Er, In/Ni) (Cr23C6 structure type) [42][43][44][45] is composed of Ni8P6 empty cuboctahedra, which connect together by means of additional Ni2 dumbbells to form a three-dimensional framework (Fig. 7A).…”