Inter cluster distance

M60 octahedra (see Fig. 4.28). The solid-state structure results from the packing of such groups. The inter-cluster distances are similar to those found in the metals. According to Simon, these compounds could be described as ([Rb902]5+, 5e ) and ([Csh03]5+, 5e ) with the five electrons donated to a conduction band, both inter-and intra-cluster metal-metal bonding, in agreement with the metallic conductivity of these compounds. 

When small clusters are placed adjacent to one another, but at random with respect to inter-cluster distances and orientations, as is the case in the amorphous arrangement of the clusters of Aujj, the interactions between the individual clusters will lead to small shifts of the intra-cluster energy levels which are slightly different for each cluster. Since both macroscopic as well as microscopic... 

For example, for diagnostics one may be interested in a minimum number of clusters (corresponding to minimization of I2) or for better generalization the inter cluster distances should be maximum... 

Although we found other examples with a roughly statistical distribution of the clusters (e.g., for styrene crosslinked by Ta404(0Et)8(0Mc)4)," " we also observed SAXS curves with two maxima instead of one. This indicates a different distribution of the clusters with two different intercluster distances. One possible explanation of the double-maximum is that the anisotropic shape (elongated disks) of some cluster types results in a kind of discotic arrangement. The shorter distance would then correspond to the inter-cluster distances within a pile of disks, and the longer distance to the distance between clusters of neighboring piles (Fig. 4). 

Similar analyses of several SAXS curves for different Fe (11) doping levels, up to 4.5 wt%, indicated that the average distance between siliceous clusters decreases for increasing Fe(II) doping (Silva, 2003). These results suggested that the Fe(ll) ions are dispersed in the polymeric matrix and that they induce a retraction effect that leads to the observed decrease in the average inter-cluster distance. 

The request that no ND4 should be within the cube is represented by n = 0. The inter-centre distance increases here so fast with x that the behaviour of the system cannot be explained with ND4 clean cubes. Since the density of nucleation centres should not increase drastically on increasing x, we have either to reduce the clean volume with x, or to allow for some stray ND4 keeping the volume constant. The latter possibility is shown in Fig. 14. The open circles correspond to the values where n is increased by one when x is increased by 0.05, starting with n = 0 for x = 0.15. It should be noted that these points still correspond to Rb-rich areas. This can be seen in Fig. 14 where the minima of the curves indicate the average concentration x = n/32. The spoiling of the nucleation centres has, of course, to be paid with a lower local transition temperature, which is indeed observed in the real system. Going along with this procedure, we would obtain cluster sizes of about 100 formula units for D-RADP-25 and of 80 formula units for D-RADP-30, i.e. of about 2 nm in... 

Table 4.1. Inter-atomic distances A(A-B) (in A) for model Si(OX)4 (X = SiH3) cluster calculated by different theoretical methods...

Alternatively, a more spherical cluster, such as a bicapped square antiprism would incorporate a C2 moiety with a C-C separation of 1.47 A and the M-M and M-C separations between 2.54 and 2.80, and ca. 1.8-2.2 A, respectively. The C2 unit is not stabilized in a square antiprismatic cavity or in other frameworks, because the inter-centroid distances are > 2.0 A, leading to C-C bond cleavage and formation of dicarbido complexes. The strength of the metal-carbide bonding is increased at the expense of the C-C bond. However, the cavity in [Nii6(C2)2(CO)23]4, is large enough to accommodate two C2 moieties. 

---