Lattice, coordination structure

The 0-0 and H-H RDFs (not shown) indicate that no 0-0 or H-H covalent bonds are formed during the simulations at all densities. The g(Roti) shows a lattice-like structure at 115 GPa, which is consistent with proton diffusion via a hopping mechanism between lattice sites.65 At 34 GPa, the coordination number for the first peak in g(RQH) is 2, which indicates molecular H20. Between 95 GPa and 115 GPa, however, the coordination number for the first peak in g(RQH) becomes four, which indicates that water has formed symmetric hydrogen bonds where each oxygen has four nearest-neighbor hydrogens. 

Fig. 6-31. Coordination structure of adsorbed water molecules on an interface of metal electrodes (a) hydrogen-bonded clusters, (b) bilayer clusters of adsorbed water molecules, (c) a superficial ( 3 x V ) KdO lattice of adsorbed water molecules on a (111) surface plane of face-centered cubic metals. (HsOli = first la] r of adsorbed water molecules. [From Thiel-Madey, 1987.]...

Where there is very strong polarization, such as in hydrogen compounds, it can happen that molecules of the type AB no longer have coordinated structures this is so in hydrogen compounds such as HG1, HBr, HI and H20. The strong polarization in these molecules would disappear if they were arranged in a coordination lattice of the NaCl or zinc-blende type. 

There are few structures known with coordination numbers larger than 8. The existence of coordination number 12 in some crystal lattices was mentioned above. Discrete nine-coordinate structures are known for complexes such as (LnlH.O) )1 and for the hydnde complexes [MHJ2- (where M = Tc or Re). These structures are formed by adding a ligand to each of the rectangular feces of a trigonal prism (Fig. 12.40). 

We have also performed calculations for higher diffusion rates (D = 100) and for the triangular lattice (coordination number z — 6). The qualitative behaviour is in complete agreement with the calculation presented here. For the case S = 1 the increase of the diffusion rate or change of the lattice structure leads to a very small shift of the phase transition point y to higher values of j/n- This trend is clear because the reactivity of the H atoms is increased by the larger mobility. For S < 1 nearly no effect is observed which means that the system s behaviour is mainly dominated by the number of activated sites. The correlation of the adsorbed particles are rather small as expected for S < 1. 

N Compoimd Formal charge Coordination Structure of anion lattice Structure type... 

In case of H-[Zn]MFI the proposed model of zinc atoms at lattice T-sites of zeolite gives not rise to presume a change of coordination structure with increasing temperature, which could be, indeed, confirmed (Fig. 4). 

The metallic radius, r etab is defined as half of the distance between the nearest-neighbour atoms in a solid state metallic lattice. However, structural data for different pol5Tnorphs of the same metal indicate that Vetai varies with the coordination number. For example, the ratio of the interatomic... 

The Fourier transform of the y-th TS unit layer, Gj(HK.Lr), is two-dimensionally periodic and the reciprocal lattice coordinate in the direction lacking periodicity is not restricted to integral values but is a real variable, labeled Lr. In Equation (22), Gj plays a role analogous to that of the atomic scattering factor in the expression of the structure factor. 

---