Complex Molecular Structures Using Cotton Swabs The use of molecular models in teaching about relatively complex structures is especially beneficial ta chemistry student and researcher alike. Frequently, the molecular models commonlyavailable are limited in scope. This point was best illustrated by my inability, with cammonly available molecular models, to reproduce the Keggin structure of the 12-molybdophosphate ion [(PMo12010)~-1.'. The difficulty arose in trying to fuse four sets of three Moo3 octahedra to the apices of a centrally located POI tetrahedron. Using cotton swabs and some fast drying glue, it was possible to reproduce the 12-molybdophosphateion. To help pinpoint specific sites in the structure, colored inka or water paints can be used. The darkened areas in the interior of the photograph represent the POI tetrahedron. This model allows one to view the interior of the structure and to introduce foreign materials: atoms, ions, ete. The limitations of the use of cotton swabs are governed only by ones' own needs. A single disadvantage of cotton swabs may he the permanency of a portion or of the total structure. This disadvantage may be partially overcome by taping or tying rather than gluing portions of the structure together.
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Cotton, F. A,. and Wilkinson, G., "Advanced Inorganic ('hemistry, A Comprehensive Text," 4th ed.. John Wiley and Suns. Inr., New York. 19R0, p. 858. Stanley C. Grenda University of Nevada, Las Vegas Las Vegas. NV 89154
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