A quasiperiodic crystal, or quasicrystal, is a structure that is ordered but not periodic. A quasicrystalline pattern can continuously fill all available space, but it lacks translational symmetry. While crystals, according to the classical crystallographic restriction theorem, can possess only two-, three-, four-, and six-fold rotational symmetries, the Bragg diffraction pattern of quasicrystals shows sharp peaks with other symmetry orders—for instance, five-fold.
William Nunn Lipscomb Jr. was a Nobel Prize-winning American inorganic and organic chemist working in nuclear magnetic resonance, theoretical chemistry, boron chemistry, and biochemistry.
X-ray crystallography is the experimental science of determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract in specific directions. By measuring the angles and intensities of the X-ray diffraction, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal and the positions of the atoms, as well as their chemical bonds, crystallographic disorder, and other information.
The University of Oviedo is a public university in Asturias (Spain). It is the only university in the region. It has three campus and research centres, located in Oviedo, Gijón and Mieres.
Hans Charles Freeman AM, FAA was a German-born Australian bioinorganic chemist, protein crystallographer, and professor of inorganic chemistry who spent most of his academic career at the University of Sydney. His best known contributions to chemistry were his work explaining the unusual structural, electrochemical, and spectroscopic properties of blue copper proteins, particularly plastocyanin. He also introduced protein crystallography to Australia and was a strong advocate for courses to ensure Australian scientists have good access to "big science" facilities. Freeman has received numerous honours, including being elected a Fellow of the Australian Academy of Science (FAA) and appointed a Member of the Order of Australia (AM) by the Australian Government. He was a charismatic lecturer who voluntarily continued teaching well into his formal retirement and imbued his students with a love of science.
M. R. N. Murthy, was a professor of molecular biophysics at the Indian Institute of Science, IISc, Bangalore. He currently teaches at the Institute of Bioinformatics and Applied Biotechnology, Bengaluru. His chief contributions are in the area of X-ray crystallography. He was awarded the Shanti Swarup Bhatnagar award for outstanding contribution to physical sciences, which is the highest honour for a scientist in India, in the year 1992.
José María Naveiras Escanlar, commonly known as Pepe el Ferreiro, was a Spanish archaeologist. He was born in Grandas de Salime, Asturias. He worked as blacksmith in the forge of his father and in other activities related to metallurgy.
The Journal of Chemical Crystallography is a peer-reviewed scientific journal publishing original (primary) research and review articles on crystallography and spectroscopy. It is published monthly by Springer Science+Business Media.
Nuclear magnetic resonance crystallography is a method which utilizes primarily NMR spectroscopy to determine the structure of solid materials on the atomic scale. Thus, solid-state NMR spectroscopy would be used primarily, possibly supplemented by quantum chemistry calculations, powder diffraction etc. If suitable crystals can be grown, any crystallographic method would generally be preferred to determine the crystal structure comprising in case of organic compounds the molecular structures and molecular packing. The main interest in NMR crystallography is in microcrystalline materials which are amenable to this method but not to X-ray, neutron and electron diffraction. This is largely because interactions of comparably short range are measured in NMR crystallography.
Aluminium triethoxide is an metallo-organic compound with the empirical formula Al(OCH2CH3)3. It is a moisture-sensitive white powder.
Topologically close pack (TCP) phases, also known as Frank-Kasper (FK) phases, are one of the largest groups of intermetallic compounds, known for their complex crystallographic structure and physical properties. Owing to their combination of periodic and aperiodic structure, some TCP phases belong to the class of quasicrystals. Applications of TCP phases as high-temperature structural and superconducting materials have been highlighted; however, they have not yet been sufficiently investigated for details of their physical properties. Also, their complex and often non-stoichiometric structure makes them good subjects for theoretical calculations.
Cerium nitrate refers to a family of nitrates of cerium in the +3 or +4 oxidation state. Often these compounds contain water, hydroxide, or hydronium ions in addition to cerium and nitrate. Double nitrates of cerium also exist.
José Joaquín Barluenga Mur was a Spanish chemist known for his research in organometallic chemistry. He was a professor of chemistry at Oviedo University until his retirement in 2014.
Aluminium triacetate, formally named aluminium acetate, is a chemical compound with composition Al(CH
3CO
2)
3. Under standard conditions it appears as a white, water-soluble solid that decomposes on heating at around 200 °C. The triacetate hydrolyses to a mixture of basic hydroxide / acetate salts, and multiple species co-exist in chemical equilibrium, particularly in aqueous solutions of the acetate ion; the name aluminium acetate is commonly used for this mixed system.
Structural chemistry is a part of chemistry and deals with spatial structures of molecules and solids. For structure elucidation a range of different methods is used. One has to distinguish between methods that elucidate solely the connectivity between atoms (constitution) and such that provide precise three dimensional information such as atom coordinates, bond lengths and angles and torsional angles.
Quantum crystallography is a branch of crystallography that investigates crystalline materials within the framework of quantum mechanics, with analysis and representation, in position or in momentum space, of quantities like wave function, electron charge and spin density, density matrices and all properties related to them. Like the quantum chemistry, Quantum crystallography involves both experimental and computational work. The theoretical part of quantum crystallography is based on quantum mechanical calculations of atomic/molecular/crystal wave functions, density matrices or density models, used to simulate the electronic structure of a crystalline material. While in quantum chemistry, the experimental works mainly rely on spectroscopy, in quantum crystallography the scattering techniques play the central role, although spectroscopy as well as atomic microscopy are also sources of information.
Ross John Angel is an internationally recognized researcher in mineralogy, expert in crystallography and elastic properties of geological materials and key industrial materials, which he studies with experimental and analytical approaches. He is the lead author or co-author of over 240 articles in international scientific journals, he received the Dana Medal from the Mineralogical Society of America in 2011 and is currently a director of research at the Institute of Geosciences and Geo-resources of the National Research Council (Italy).
Robert Day Shannon is a retired research chemist formerly at DuPont de Nemours, Inc.
Janos Hajdu is a Swedish/Hungarian scientist, who has made contributions to biochemistry, biophysics, and the science of X-ray free-electron lasers. He is a professor of molecular biophysics at Uppsala University and a leading scientist at the European Extreme Light Infrastructure ERIC in Prague.
Disulfidobis(tricarbonyliron), or Fe2(μ-S2)(CO)6, is an organometallic molecule used as a precursor in the synthesis of iron-sulfur compounds. Popularized as a synthetic building block by Dietmar Seyferth, Fe2(μ-S2)(CO)6 is commonly used to make mimics of the H-cluster in [FeFe]-hydrogenase. Much of the reactivity of Fe2(μ-S2)(CO)6 proceeds through its sulfur-centered dianion, [Fe2(μ-S)2(CO)2]2-.
