Tetragonal bonds

Fig. 21 Energy level diagram for occupancy of Ti and Mn d transition metal atom d-states within the forbidden energy gap. (a) Ti d occupied states in Ti02- (b) Mn d occupied 3d states in a high spin tetragonal bonding arrangement [14] and (c) Mn d occupied 3d states in a high spin bipyramidal bonding arrangement...

NakayamaS however, has suggested that, for rutile, which is tetragonal in structure, the strong bond between metal and oxide results from the favourable spacing between titanium ions in the rutile lattice and those in the metal structure. This explanation, however, does not account for the fact that other oxides of titanium, such as brookite, which is orthorhombic, and anatase, which is tetragonal, are also protective . 

PdF2 is that rare substance, a paramagnetic palladium compound, explicable in terms of (distorted) octahedral coordination of palladium with octahedra sharing corners [15], It exists in two forms, both having /zeff 2.0 /xB, rather below the spin only value for two unpaired electrons. Bond lengths are Pd-F 2.172 A (two) and 2.143 A (four) in the tetragonal form (rutile structure). 

Absorption spectra and ligand field parameters of tetragonal 3transitional metal fluorides. D. Oelkrug, Struct. Bonding (Berlin), 1971, 9,1-26 (91). 

The tetragonal crystal WSi2 (Zachariasen, 1927) may serve as another example. Each silicon atom forms five bonds with surrounding silicon atoms at 2-633 A and five bonds with tungsten atoms at the same distance. Each tungsten atom forms ten bonds with silicon atoms at 2-633 A and four bonds with tungsten atoms at... 

The foregoing discussion leads to the conclusion that static deformations as well as phonons should be stabilized for superconducting metals by the change in effective radius associated with unsynchronized resonance of electron-pair bonds. Deformation from cubic to tetragonal symmetry, presumably the result of this interaction, has been reported for VsSi at temperatures below 21 K26- 27 and for Nb2Sn at temperatures below 43°K.28... 

A crystal-structure determination on [Ni(PhCH2CS2)2] showed evidence of a Ni-Ni bond (Ni—Ni distance, 256 pm) in a bridging, acetate-cage, binuclear complex (363). Each nickel atom is 5-coordinate and is in a tetragonally distorted, square-pyramid spectroscopic evidence for a Ni-Ni bond has been obtained (364). The polarized crystal spectra showed more bands than predicted for a mononuclear, diamagnetic, square-planar nickel(Il), and the spectra are indicative of substantial overlap of the d-orbitals between the two nickel atoms. The bis(dithiobenzation)nickeKII) complex was found to exhibit unusual spectrochemical behavior (365). 

In the crystal structure of these phases with tetragonal symmetry (P4/mbm, D h) the boron covalent sublattice is formed by chains of octahedra, developing along the c axis and by pairs of B atoms, bonding the octahedra in the xOy plane (see Fig. 1). The resulting three-dimensional skeleton contains tunnels parallel to the c axis that are filled by metal atoms . ... 

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