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A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and biochemistry, the distinction from ions is dropped and molecule is often used when referring to polyatomic ions.
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.
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Sodalite is a tectosilicate mineral with the formula Na
8(Al
6Si
6O
24)Cl
2, with royal blue varieties widely used as an ornamental gemstone. Although massive sodalite samples are opaque, crystals are usually transparent to translucent. Sodalite is a member of the sodalite group with hauyne, nosean, lazurite and tugtupite.
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Solid oxygen forms at normal atmospheric pressure at a temperature below 54.36 K (−218.79 °C, −361.82 °F). Solid oxygen O2, like liquid oxygen, is a clear substance with a light sky-blue color caused by absorption in the red part of the visible light spectrum.
Dan Shechtman is the Philip Tobias Professor of Materials Science at the Technion – Israel Institute of Technology, an Associate of the US Department of Energy's Ames National Laboratory, and Professor of Materials Science at Iowa State University. On April 8, 1982, while on sabbatical at the U.S. National Bureau of Standards in Washington, D.C., Shechtman discovered the icosahedral phase, which opened the new field of quasiperiodic crystals.
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References
- ↑ Urban, Knut; Feuerbacher, Michael (2004). "Structurally complex alloy phases". Journal of Non-Crystalline Solids. 334–335. Elsevier B.V.: 143–150. Bibcode:2004JNCS..334..143U. doi:10.1016/j.jnoncrysol.2003.11.029.
- ↑ Dubois, Jean-Marie; Belin-Ferré, Esther, eds. (2011). Complex Metallic Alloys: Fundamentals and Applications. Wiley-VCH. doi:10.1002/9783527632718. ISBN 978-3-527-32523-8.
- ↑ Pauling, Linus (1923). "The Crystal Structure of Magnesium Stannide". Journal of the American Chemical Society. 45 (12). American Chemical Society (ACS): 2777–2780. doi:10.1021/ja01665a001. ISSN 0002-7863.
- ↑ Pauling, Linus (1955). "The Stochastic Method and the Structure of Proteins". American Scientist. 43 (2): 285–297. JSTOR 27826614.
- ↑ "Complex Metallic Alloys". Community Research and Development Information Service (CORDIS). Retrieved 2023-08-26.
- ↑ "European Integrated Centre for the Development of New Metallic Alloys and Compounds" . Retrieved 2023-08-26.
- ↑ Samson, S. (1965-09-01). "The crsytal structure of the phase β Mg2Al3". Acta Crystallographica. 19 (3). International Union of Crystallography (IUCr): 401–413. doi:10.1107/s0365110x65005133. ISSN 0365-110X.
- ↑ Boudard, M.; Klein, H.; Boissieu, M. De; Audier, M.; Vincent, H. (1996). "Structure of quasicrystalline approximant phase in the Al-Pd-Mn system". Philosophical Magazine A. 74 (4). Informa UK Limited: 939–956. Bibcode:1996PMagA..74..939B. doi:10.1080/01418619608242169. ISSN 0141-8610.
- ↑ Smontara, A.; Smiljanić, I.; Bilušić, A.; Jagličić, Z.; Klanjšek, M.; Roitsch, S.; Dolinšek, J.; Feuerbacher, M. (2007). "Electrical, magnetic, thermal and thermoelectric properties of the "Bergman phase" Mg32(Al,Zn)49 complex metallic alloy". Journal of Alloys and Compounds. 430 (1–2). Elsevier BV: 29–38. doi:10.1016/j.jallcom.2006.05.026. ISSN 0925-8388.
- ↑ Taylor, M. A. (1961-01-10). "The space group of MnAl3". Acta Crystallographica. 14 (1). International Union of Crystallography (IUCr): 84. Bibcode:1961AcCry..14...84T. doi: 10.1107/s0365110x61000346 . ISSN 0365-110X.
- ↑ Hiraga, K.; Kaneko, M.; Matsuo, Y.; Hashimoto, S. (1993). "The structure of Al3Mn: Close relationship to decagonal quasicrystais". Philosophical Magazine B. 67 (2). Informa UK Limited: 193–205. Bibcode:1993PMagB..67..193H. doi:10.1080/13642819308207867. ISSN 1364-2812.