A study of the Phase Mg2Cu6Ga5, Isotypic with Mg2Zn11. A Route to an Icosahedral Quasicrystal Approximant
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Ames National Laboratory is a government-owned, contractor-operated national laboratory of the U.S. Department of Energy (DOE), operated by and located on the campus of Iowa State University in Ames, Iowa.
For more than 70 years, the Ames National Laboratory has successfully partnered with Iowa State University, and is unique among the 17 DOE laboratories in that it is physically located on the campus of a major research university. Many of the scientists and administrators at the Laboratory also hold faculty positions at the University and the Laboratory has access to both undergraduate and graduate student talent.
The Department of Chemistry seeks to provide students with a foundation in the fundamentals and application of chemical theories and processes of the lab. Thus prepared they me pursue careers as teachers, industry supervisors, or research chemists in a variety of domains (governmental, academic, etc).
History
The Department of Chemistry was founded in 1880.
Dates of Existence
1880-present
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- College of Liberal Arts and Sciences (parent college)
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Abstract
The new title compound was synthesized by high-temperature means and its X-ray structure refined in the cubic space group Pm3̄, Z = 3, a = 8.278(1) Å. The structure exhibits a 3-D framework made from a Ga14 and Mg network within which large and small cavities are occupied by centered GaCu12 icosahedral and Cu6 octahedral clusters, respectively. The clusters are well bonded within the network. Electronic structure calculations show that a pseudogap exists just above the Fermi energy, and nearly all pairwise covalent interactions remain bonding over a range of energy above that point. Analysis suggests that the compound is hypoelectronic with a four-electron deficiency per unit cell, and such a derivative with Sc substituting for Mg is an appropriate quasicrystal approximant (Im3̄). Such characteristics seem to be key factors in the formation of icosahedral quasicrystals.
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This article is from Inorganic Chemistry 42 (2003): 8762, doi: 10.1021/ic030191h. Posted with permission.