Fei Wang - EuAgxAl11-x with the BaHg11-Type Structure: Coloring, Composition, and Competition with the BaCd11-Type Structure

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      Publication Details (including relevant citation   information):

      Wang, F.; Pearson, K. N.; Straszheim, W. E.; Miller, G. J.; Chem.   Mater. 2010, 22, 1798.


      EuAgxAl11−x phases   adopting the BaHg11-type structure (space group   Pmm, Z = 3) were synthesized with   high yield by arc melting a mixture loaded as   “EuAg3.5Al7.5” and annealing at 500 °C for   40 days. This phase has a very narrow phase width around   EuAg4.0Al7.0; and it is unstable at 600 and   700 °C, at which it transforms into other phases. Magnetometry   indicates that Eu is divalent, which gives the valence electron   concentration per Ag/Al atom as 2.45 e/atom, higher   than in the BaCd11-type phases in the Eu−Ag−Al system   (2.10−2.30 e/atom). First principles electronic   structure calculations, using a computational model structure   built by simulating the crystallographic results as well as   maximizing the number of heteroatomic (Ag−Al) contacts, can   explain why the cubic BaHg11-type structure is favored   at higher valence electron concentration than the tetragonal   BaCd11-type structure.

      Address (URL): http://pubs.acs.org/doi/citedby/10.1021/cm903300y