threefold symmetry

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• Rotational symmetry — Generally speaking, an object with rotational symmetry is an object that looks the same after a certain amount of rotation. An object may have more than one rotational symmetry; for instance, if reflections or turning it over are not counted, the …   Wikipedia

• Mirror symmetry (string theory) — In physics and mathematics, mirror symmetry is a relation that can exist between two Calabi Yau manifolds. It happens, usually for two such six dimensional manifolds, that the shapes may look very different geometrically, but nevertheless they… …   Wikipedia

• quasicrystal — /kway zuy kris tl, kway suy , kwah see , zee /, n. a form of solid matter whose atoms are arranged like those of a crystal but assume patterns that do not exactly repeat themselves. [1985 90] * * * Introduction also called  quasi periodic crystal …   Universalium

• Solar symbol — A solar symbol is a symbol which symbolises the Sun. Solar symbols can have significance in psychoanalysis, symbolism, semiotics, astrology, religion, mythology, mysticism, divination, heraldry, and vexillology, among other fields.Some solar… …   Wikipedia

• Metal nitrosyl complex — Metal nitrosyl complexes are complexes that contain nitric oxide, NO, bonded to a transition metal.[1] Many kinds of nitrosyl complexes are known, which vary both in structure and coligand. Contents 1 Bonding and structure 1.1 Linear vs bent… …   Wikipedia

• Cyclol — Figure 1: In the classic cyclol reaction, two peptide groups are linked by a N C’ bond, converting the carbonyl oxygen into a hydroxyl group. Although this reaction occurs in a few cyclic peptides, it is disfavored by free energy, mainly because… …   Wikipedia

• Snow — Snowfall redirects here. For other uses, see Snow (disambiguation) or Snowfall (disambiguation). Snow is a type of precipitation in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. The process of… …   Wikipedia

• Tribrachidium — Taxobox name = Tribrachidium heraldicum image caption = Fossil of Tribrachidium heraldicum image2 caption = Colourful reconstruction fossil range = fossil range|558|542Ediacaran 558 542Ma [cite journal author = Grazhdankin, Dima year = 2004 title …   Wikipedia

• isometric system — ▪ crystallography also called  Cubic System,         one of the crystal systems to which a given crystalline solid can be assigned. Crystals in this system are referred to three mutually perpendicular axes of equal lengths. If the atoms or atom… …   Universalium

• Ice — This article is about water ice. For the broader concept of ices as used in the planetary sciences, see volatiles. For other uses, see Ice (disambiguation) …   Wikipedia

• Oxocarbon anion — 2D diagram of mellitate C12O6− 12, one of the oxocarbon anions. Black circles are carbon atoms, red circles are oxygen atoms. Each blue halo represents one half of a negative charge. In chemistry, an oxocarbon anion is a …   Wikipedia