Face-sharing octahedra

Take pairs of face-sharing coordination octahedra and join them by common vertices to form a chain, with every octahedron taking part in one common vertex not belonging to the shared face. What is the composition of the resulting chain ... 

In the RuBr3 type a succession of face-sharing octahedra form a strand in the c direction. The metal atoms in adjacent octahedra are shifted in pairs from the octahedron centers, forming metal-metal bonds (Fig. 16.10, p. 175). This seems to be the condition for the existence of this structure type, i.e. it only occurs with transition metals that have an odd-numbered d electron configuration. 

Figure 4.38 Idealized structure of SrxTiS3 modulated phases (a) an idealized TiS6 octahedron (the shaded faces are shared to form columns) (b) idealized hexagonal unit cell formed by columns of face-shared TiS6 octahedra (c) idealized unit cell formed by columns of face-sharing octahedra and Sr atoms (shaded) and (d) idealized structure of Sr8(TiS3)7.

In the protonation of the trianion to the dianion, the second hydrogen occupies an adjacent face-shared octahedron in the dodecanickel fragment. The... 

The core of the [Fe6Ni6(N)2(CO)24]2- cluster comprises a central Ni6 octahedron that shares a pair of opposite faces with two Ni3Fe3 octahedra, as shown in Fig. 19.4.3(c). The interstitial N atoms occupy the centers of the Ni3Fe3 octahedra. Each Fe atom has two terminal carbonyl groups, and each Ni atom has one. 

Figure 5.4 The corundum crystal structure (a) projected down the c axis showing layers of edge-shared [A106] octahedra with one octahedron vacant for every two Al3+ ions (b) section perpendicular to the c axis showing pairs of Al3+ ions in face-shared [A106] octahedra (c) configuration of the trigonally distorted [A106] octahedra with point symmetry C3 projected onto the (0001) plane.

A second type of [E3X12]3 structure is found in the complexes [Et3-NH]3[As3Br12] (71) (83, 84) and [Me3NH]3tAs3I12] (72) (84) a view of 72 is shown in Fig. 15. In this instance, the structure can be viewed as being derived from an [EX6]3 octahedron in which two faces sharing a common vertex have been capped by EX3 units. This results in termi-... 

The ultramarine and sodalite framework lattice is shown in Figure 2.29. This framework results when the square faces of the truncated octahedron are shared. Again, the perspective in the figure emphasizes the possibility of constructing the extended lattice of P4-3m symmetry. 

In CsNiCls, ions of Cs and Cl form close-packed layers which are stacked as... ABABAB... Ions of Ni are in between these layers. They form linear chains of face-sharing octahedrons [NiC ]. In CsCuCls, however, each octahedron [CuCl6] is in electron configuration 3d with JT-unstable ground state Eg, quite similar to the abovementioned example of [CuF6] in KCuFs (Sect. 3.2). 

Fig. 12 Hexagonal perovskite crystal structure of the parent compound CsNiCfi. Black circles represent transition metal atoms, Ni in this case. White circles are ligands. Shaded circles are atoms of Cs . Face-sharing octahedrons [NiCle] are packed in linear chains (From [57])...

Face-sharing between coordination polyhedra in a heteropolyanion was first detected in CeMoi2Oii2 (23). The MoOg octahedra form six facesharing pairs (Fig. 6) corners are shared between octahedra in different pairs, and in addition each octahedron shares a face with the central... 

The three ways to combine F polyhedra (octahedron) two by two (F[i]F) are shown in 3. The first possibility 3a corresponds to a face sharing ([c] type connection), the second one 3b to an edge sharing ([b] type connection), and the third one 3c to an apex sharing ([a] type connection). 

Figure 25.13 Metal frameworks of some Ru and Os carbonyl clusters with interstitial atoms, (a) [Ru8(H)2(CO)2i] (octahedron and face-sharing trigonal bipyramid) the second H is probably at the centre of the octahedron. (b) [Ru8(C)2(CO)n(PPh2)2] (octahedron and face-sharing square pyramid) PPh2 ligands bridge the pairs of shaded Ru atoms, (c) [Os7(H)2C(CO)i9] (tetrahedron and 3 irregularly spaced metal atoms) H atoms probably bridge two edges of the tetrahedron.

The minerals of the burangaite, Na[Fe Al5(P04)4(OH)6(H20)2], group contain a trimer of face-sharing octahedra that is a feature of several basic iron-phosphate minerals (Moore 1970). An (Fe ( )6) octahedron shares two trans faces with (Al( )6) octahedron to form a trimer of the form (the h cluster of Moore 1970). This trimer is corner... 

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