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The simplest examples of organic molecules displaying inverted tetrahedral geometry are the smallest propellanes, such as [1.1.1]propellane; or more generally the paddlanes, [9] and pyramidane ([3.3.3.3]fenestrane). [7] [8] Such molecules are typically strained, resulting in increased reactivity.
Tetrahedrane is a hypothetical platonic hydrocarbon with chemical formula C 4 H 4 and a tetrahedral structure. The molecule would be subject to considerable angle strain and has not been synthesized as of 2023.
Branched polyphosphoric acids give similarly branched polyphosphate anions. The simplest example of this is triphosphono phosphate [OP(OPO 3) 3] 9− and its partially dissociated versions. The general formula for such (non-cyclic) polyphosphate anions, linear or branched, is [H n+2−k P n O 3n+1] k−, where the charge k may vary from 1 to n + 2.
For example, in the mineral orthoclase [KAlSi 3 O 8] n, the anion is a tridimensional network of tetrahedra in which all oxygen corners are shared. If all tetrahedra had silicon centers, the anion would be just neutral silica [SiO 2] n. Replacement of one in every four silicon atoms by an aluminum atom results in the anion [AlSi 3 O − 8]
For example, sulfur hexafluoride (SF 6) is an octahedral molecule. Trigonal pyramidal : A trigonal pyramidal molecule has a pyramid-like shape with a triangular base. Unlike the linear and trigonal planar shapes but similar to the tetrahedral orientation, pyramidal shapes require three dimensions in order to fully separate the electrons.
A uniform compound of four tetrahedra can be constructed by rotating tetrahedra along an axis of symmetry C 2 (that is the middle of an edge) in multiples of /.It has dihedral symmetry, D 8h, and the same vertex arrangement as the convex octagonal prism.
This configuration, like Möbius, can also be represented as two tetrahedra, mutually inscribed and circumscribed: in the integer representation the tetrahedra can be 0347 and 1256. However, these two S 4 configurations are non-isomorphic, since Möbius has four pairs of disjoint planes, while the latter one has no disjoint planes. For a ...
The divalent metal carboxylate based frameworks MOF-5 and HKUST-1 are examples of prototypical MOF materials and triggered a huge growth in the field of metal-organic frameworks. A keyword search for “metal-organic frameworks” registers>1,600 publications in 2010 and >2,000 for 2011, a strong indication of the worldwide interest in this ...