Samson complexes

Figure 19. (a) Two views of the partitioning of the 12 vertices of a regular icosahedron into six rhombohedral vertices (R) and six equatorial vertices (E) upon reduction from It, to symmetry, (b) The Samson complex derived from a truncated icosahedron, which is found in the /3-rhombohedral boron structure, (c) The 28-vertex polyhedral cavities formed by overlap of the equatorial pentagonal pyramidal cavities of three Samson complexes in the -rhombohedral boron structure. 

FIG. 2. A complex of twenty Friauf polyhedra, with icosahedral symmetry (Samson, Ref. 23). This complex contains 104 atoms, if the central icosahedral position is not occupied. Most of the atoms show approximate icosahedral ligan-cy twenty atoms, at the centers of the Friauf polyhedra, have ligancy 15 or 16. The complex was first identified in Mg32(Al,Zn)<9. In the cubic crystals that form the icosatwins and decatwins these complexes are packed in such a way as to approximate an icosahedral arrangement of twelve complexes about a central one, the structure being similar to that of 0-W. 

The pipelining for modifiers is more complex the control for each modifier is different and is therefore not detailed here (see figure 4 of [Samson, 1980] for a sketch... 

Sten Samson, The structure of complex intermetallic compounds, in Structural Chemistry and Molecular Biology A Volume Dedicated to Linus Pauling by his Students, Colleagues, and Friends, A. Rich and N. Davidson, eds., W. H. Freeman, San Francisco, 1968, pp. 687-718. 

Wood S. A. and Samson I. M. (1998) Solubility of ore minerals and complexation of ore metals in hydrothermal solutions. In Techniques in Hydrothermal Ore Deposits Geology (eds. J. Richards and P. Larson). Reviews in Economic Geology, pp. 33-80. 

Evans HC, Samson RA. Cordyceps species and their anamorphs pathogenic on ants (Formicidae) in tropical forest ecosystems. I. The Cephalotes (Myrmicinae) complex. Trans Br Mycol Soc 79 431-453, 1982a. 

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