Qisheng Lin, Trinath Mishra, John D Corbett; manuscript in preparation.

1. Unprecedented hexagonal-diamond-like lattice of pure Au in Ba2Au6(Au,T)3 (T = Zn, Cd, Ga, In, Sn) John D. Corbett, Iowa State University, DMR 0853732 Aggregates or fragments of gold with different geometries have been widely expanded in recent years in Au-rich intermetallics, e.g., as condensed tetrahedra in K3Au5In, hexagonal stars in Ca14Au46Sn5,square pyramids in SrAu3Ge,and sinusoid layers in Ca4Au10In3. However, there is no practical way to anticipate or predict a truly novel structure, and such an hexagonal diamond-like lattice of pure Au has never been reported. The new structure Ba2Au6(Au,T)3 (b), now known with T = Zn, Cd, Ga, In, Sn, contains an hexagonal diamond-like lattice of Au and has a topological relationship with the Au sheets and Ba columns in BaAu2 (a). The triangular (Au,T)3 units (green) replace one-third of the Ba in columns and also exhibit some variability in Au:T. Qisheng Lin, Trinath Mishra, John D Corbett; manuscript in preparation.

2. Broader Impacts John D. Corbett, Iowa State University, DMR 0853732 The results of our exploratory synthetic efforts together with their various characterization outputs, including bonding descriptions, bring with them the expectation that at least the more unusual or unprecedented discoveries will be considered, investigated, or advertised with respect to the conceived, imagined or possible usefulness or applications of each. Nonetheless, these types of materials may be furthest from present utility, and the explorers are also apt to be relatively ignorant of any application details, criteria, problems, or lore. These barriers of course should also lead to an early effort to publish the new results. The particularly novel aspects of our frequent discoveries are further handicapped by the general condensed, solid state characteristics of ternary intermetallics, and the lack of information about their reactions with the ambient environments. Notwithstanding, some general ideas come up. Interests in colloidal-, nano- or other gold substrates for catalysis is evident, often just in elemental form,, and we have exotic derivatives for which surface instead of bulk reactions are unknown. The presence of a cation (Ba, an electron donor) is a different feature as well. We could also imagine chemically pushing the Au 5d orbitals higher, closer to Fermi, to make it less noble. Or should we push them lower? Of course, heterogeneous catalysis implicates surface properties, befitting under-coordinated atoms, and ours gain stability and unfamiliar characteristics with tighter bound states. These contrasts or contradictions also suggest we need to explore the solid state world of gold more widely, and what about Pt, Pd, Ag, etc. components? Two undergraduates have also learned some rudiments of such research in our laboratories in the past year, Jordan Vetter, a freshman, and Ran Zhu, a junior in chemistry.