Triangular bipyramidal

Geometry pyramidal triangular bipyramidal tetrahedral octahedral tetrahedral... 

In any molecule in which there are no nonbonding pairs around the central atom, the molecular shape is the same as the molecular geometry. Thus, to use the examples from Table 6.2, all three two-substituent molecules have both a linear geometry and a linear shape. Both BH3 and H2CO have a triangular planar shape, CH4 has a tetrahedral shape, PF5 a triangular bipyramidal shape, and SF6 a square bipyramidal shape. 

What is the shape of a chlorine trifluoride molecule, C1F3, which has a triangular bipyramidal geometry ... 

In total, many different container molecules of various shapes like tetrahedra, octahedra, cubes, triangular bipyramids, dodecahedra, icosahedra, cuboctahedra or various shaped prisms or antiprisms have been described in the literature up to now [6-10]. Altogether they are far too many to be described in detail. Therefore this chapter focuses only on container molecules based on imine type ligands. 

Symmetry operations in the point group D3h (6m2), applicable to a triangular bipyramid of that symmetry. The corners of the bipyramid are labeled A, B, C, D, E. The symmetry operations are two vertical threefold axes C3 (clockwise rotation by 120°) and C3 (counterclockwise rotation by 120°, or counterclockwise by 240°), three horizontal twofold axes C2, C2, and C2", and three vertical symmetry planes av, [Pg.395]

Effect of 11 of the 12 symmetry operators (all except identity) of point group D3h (6m2) on a triangular bipyramid (think of the molecule PCI5), with five marked vertices A, B, C, D, and E (the chlorine atoms). 

Using this reasoning, we can predict that an AX4E molecule (that is, a molecule in which the central atom A is coordinated to four other atoms X and to one nonbonding electron pair) such as SF4 will have a see-saw shape substitution of more nonbonding pairs for bonded atoms reduces the triangular bipyramid coordination to even simpler molecular shapes, as shown below. (See the examples on the next page.)... 

The minerals of the triploidite, [Mn 2(P04)(0H)], group have divalent cations in both octahedral and triangular bipyramidal coordinations. Pairs of octahedra share an edge to form [M 2(t>io] dimers, and these dimers are linked by sharing corners with both... 

Figure 50. The crystal structures of althausite, hureaulite and thadeuite (a) althausite projected onto (010) (b) althausite projected onto (100) (Mgc )6) octahedra are shadow-shaded, (Mg( )5) triangular bipyramids are line-shaded (c) hureaulite projected onto (001) (d) hureaulite projected onto (010) (Mn ( )6) octahedra are shadow-shaded (e) thadeuite projected onto (010) (f) thadeuite projected onto (100) (Mg(j)6) octahedra are shadow-shaded.

Senegalite, [Al2(P04)(0H)3(H20)], contains Al in both triangular bipyramidal and octahedral coordinations. (A s) and (A e) polyhedra share an edge to form a dimer, and these dimers link by sharing comers to form a [ Al A g] chain that extends in the [101] (and [101]) direction (Fig. 57a). These chains are decorated by (PO4) groups that link them to form a slab parallel to (010). These slabs stack in the -direction, and link by sharing tetrahedron-octahedron and tetrahedron-bipyramid corners (Fig. 57b). This framework is fairly open, and the interstices are criss-crossed by a network of hydrogen bonds. 

Organoantimony (V) dihalides exist in a triangular bipyramidal geometry with the typically bond angles as shown below for trimethylantimony dichloride (1). The two halides reside in the axial positions whereas the organic moieties are present on the equalitorial plane. 

Icosahedron Pentagonal bipyramid Octahedron Triangular bipyramid Tetrahedron... 

For small v compact structures are obtained which have maximal average coordination number z t > 0). For example, for v = 2, the ground-state structures are the triangle, tetrahedron, triangular bipyramid, capped bipyramid and pentagonal bipyramid for N =... 

The VSEPR theory predicts that the five electron groups around the phosphorus atom in PF5 should be as far apart as possible. Maximum separation of five electron groups around a central atom is achieved when the five electron groups (bonding pairs) are placed at the corners and the central atom (P) is placed in the center of a trigonal (or triangular) bipyramid. This is in agreement with experimental observation. 

The trivalent rare earths are in one 8-prismatic and in one special 7-coor-dinated site. The divalent elements, europium (II), strontium or lead, are in 7- or 8-coordinated prisms. The tin IV occupies two nearly octahedral sites and one 5-coordinated triangular bipyramidal site. Other possibilities exist for the filling of the sites with the formation of superstructures. 

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