title: Network Formation by Condensed Tetrahedral [Au3Al] Units in Na2Au3Al: Crystal and Electronic Structure, Spectroscopic Investigations, and Physical Properties of an Ordered Ternary Auride.
abstract: Na2Au3Al, the first experimentally prepared compound in the ternary Na-Au-Al system, crystallizes in the cubic crystal system with space group P4132 (a = 771.42(2) pm). It can be described as a P-centered ternary ordered variant of the F-centered Laves phase MgCu2and is isostructural to Mo3Al2C. A phase width was found for the series Na2Au4-xAlxallowing a successive substitution of Au by Al. The primitive structure forms for x ≥ 0.5. Na2Au3Al is diamagnetic at room temperature but metallic in nature, as seen from susceptibility and electrical resistivity measurements. Band structure calculations and X-ray photoelectron spectroscopy confirm the metallic nature of the title compound as states are found at the Fermi level of the DOS, along with its "auride" character.23Na and27Al solid-state-NMR investigations show the existence of both a disordered (x = 0.5 and 0.75) and a fully ordered (x = 1.0) representative within this series. Both COHP and Bader charge analyses suggest the presence of strong Au-Al interactions forming an anionic [Au3Al]δ-network, with the Na cations occupying the cavities.
authors.affiliation: Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster , Corrensstrasse 28, D-48149 Münster, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Stegemann
authors.affiliation: Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster , Corrensstrasse 28, D-48149 Münster, Germany.|Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster , Corrensstrasse 30, D-48149 Münster, Germany.
authors.forename: Christopher
authors.initials: C
authors.lastname: Benndorf
authors.affiliation: Department of Chemistry, University of California, Riverside , 501 Box Springs Rd, Riverside, California 92521, United States.
authors.forename: Yuemei
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Physikalisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Strasse 10, D-48149 Münster, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Bartsch
authors.affiliation: Physikalisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Strasse 10, D-48149 Münster, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Zacharias
authors.affiliation: Department of Chemistry, University of California, Riverside , 501 Box Springs Rd, Riverside, California 92521, United States.
authors.forename: Boniface P T
authors.identifier: http://orcid.org/0000-0001-9802-7815
authors.initials: BP
authors.lastname: Fokwa
authors.affiliation: Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster , Corrensstrasse 30, D-48149 Münster, Germany.|Instituto de Física de São Carlos, Universidade de São Paulo , São Carlos-SP 13566-590, Brazil.
authors.forename: Hellmut
authors.identifier: http://orcid.org/0000-0002-6536-0117
authors.initials: H
authors.lastname: Eckert
authors.affiliation: Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster , Corrensstrasse 28, D-48149 Münster, Germany.|Institut für Chemie, Carl von Ossietzky Universität Oldenburg , Carl-von-Ossietzky Strasse 9-11, D-26129 Oldenburg, Germany.
authors.forename: Oliver
authors.identifier: http://orcid.org/0000-0002-9480-3888
authors.initials: O
authors.lastname: Janka