Apical bridging oxygen

The (110) rutile surface has two different types of oxygen present. The four oxygen atoms that surround the coordinatively unsaturated Ti cation (5f, Fig. 5.4b) have no charge excess. The apical bridging oxygen atoms o, Fig- 5.4b), however, have an ion charge excess e (0) = — ... 

Figure 6.19. O MAS NMR spectra of Li2Ti0Si04 and Li2Ti0Ge04 showing the resonances from the apical and bridging oxygen atoms. The asterisks denote spinning side bands from the apican oxygen resonances. From Bastow et al. (1999) by permission of the copyright owner.

Figure 8 One layer of the framework structure of hydrated VPI-5 taken from the stereoscopic view along the [001] direction according to McCusker et al. 80], showing the deviation from P6,cm symmetry. Aluminum and phosphorus atoms, linked via oxygen atoms (not shown for clarity), are located at the apices of the p)olygons. Sites located between two fused four-membered rings are known as 4-4 sites those located between six-membered and four-membered rings are known as 6-4 sites. P2 and P3, and A12 and A13 sites are inequivalent as a result of the distortion. The All site is six-coordinated as a result of bonding to four bridging oxygens and two framework water molecules. Other intracrystalline water is not shown.

In this case, one of the apical oxygens of one tetrahedron is shared with another tetrahedron, i.e. one bridging oxygen in each tetrahedron (Fig. 3.3A). The basic structural imit is Si207 . Example Hemimorphite - Zn4Si207(0H) H20. 

In the mcthoxy-complex (77) the metal has a distorted square-pyramidal co-ordination the basal sites are occupied by two bridging oxygen atoms, a nitrogen, and a chlorine atom, the Cu-N and Cu-Cl distances being 2.01(1) and 2.265(4) A. The apical position contains the chlorine atom of an adjacent dimeric unit the Cu-Cl(apical) distance of 2.944(4) A is rather long. The Cu-Cu distance between metal atoms in different dimers is 2.80 A, rather shorter than the corresponding value of 3.02 A between metal atoms in the same dimer. 

From Mossbauer data, it was concluded that RSbO 3H2 are trigonal bipyramids with bridging oxygens in apical positions. ... 

The late transition metals, either Co or Ni, bond to four apical oxygen atoms of two vertex-shared 5 units (Fig. 17.9a), two each to layers both above and below, and also bond to two bridging pyrazine ligands in a trans fashion. The al-... 

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