R₁₄(Au, M)₅₁ (R = Y, La–Nd, Sm–Tb, Ho, Er, Yb, Lu; M = Al, Ga, Ge, In, Sn, Sb, Bi): Stability Ranges and Site Preference in the Gd₁₄Ag₅₁ Structure Type

Abstract

Sb, Bi) using solid state synthesis techniques. The list of post transition metals (M) involved in the formation of this type of structure could be augmented by five new representatives. All compounds crystallize in the hexagonal space group P6/m (#175) with the unit cell ranges of a = 12.3136(2)−12.918(1) Å and c = 8.9967(3)−9.385(1) Å, and incorporate different degrees of Au/M mixing. The involvement of the post transition element in the structure varies from one to another compound both qualitatively and quantitatively. A rather significant phase width can be expected for the majority of compounds, however, not without exclusions. The distribution of the post transition metals within the structure has been analyzed via single crystal X-ray diffraction. While the positional disorder of one near-origin Au position is expectable for all compounds due to steric reasons, two specimens show an obvious deviation from the others including another Au position split along the c axis. Possible factors affecting this behavior are discussed.

Metallic alloys at the edge of complexity: structural aspects, chemical bonding and physical properties*

“…It is worth noting that Au appears to serve as an efficient trigger of structural complexity in trielides. Although gold compounds are known to display different sorts of polyanionic units with varying degrees of complexity, most of such phases are not classified as CMAs following the definition used in the present work [164,[233][234][235][236][237][238][239][240]]. Yet, many gold-bearing trielides demonstrate exceedingly large unit cells with a high number of atoms.…”

Overlooked Binary Compounds Uncovered in the Reinspection of the La–Au System: Synthesis, Crystal Structures, and Electronic Properties of La7Au3, La3Au2, and La3Au4

“…In many cases, induction or arc furnaces are utilized for these purposes. 15 − 18 Because of the high reaction temperatures, mainly thermodynamically stable compounds are produced by such methods. Since diffusion rates drop considerably with decreasing temperature, targeting metastable or low-temperature phases is challenging, especially when various compositionally close phases exist in the system.…”

“…Gold-containing intermetallics are conventionally produced by annealing Au with other metals at elevated temperatures, usually close to or above the melting point of some or all of the reactants. In many cases, induction or arc furnaces are utilized for these purposes. − Because of the high reaction temperatures, mainly thermodynamically stable compounds are produced by such methods. Since diffusion rates drop considerably with decreasing temperature, targeting metastable or low-temperature phases is challenging, especially when various compositionally close phases exist in the system .…”