Development of computer generated structural models: Teaching aids in soil mineralogy Varadachari Chandrika1, Ghosh Kunal2,* 1Raman Centre for Applied and Interdisciplinary Sciences, 16A, Jheel Road, Calcutta, 700 075 2Department of Agricultural Chemistry & Soil Science, University of Calcutta, 35, Ballygunge Circular Road, Calcutta, 700 019 *This invitational lecture was delivered by Dr. K. Ghosh during the 14th Annual Convention of the Clay Minerals Society of India held at NRL, IARI, New Delhi during 11-2 August, 2005. Abstract Computer programs and graphics provide new generation tools for constructing structural models of minerals. These models can be rotated, providing views of different surfaces and angles, and can be subjected to ‘virtual’ reactions. Thereby, conceptualisation of mineral structures and understanding their reactivity or formation are greatly simplified. In this paper, we have presented development of 3D structures of minerals based on mathematical computation of the atomic positions in the crystal. This was used as input into the program RasMol or Moldraw to enable viewing and molecular rotation. Structures for oxides like goethite, hematite, gibbsite and boehmite were derived and their reactions with phosphate visualised. Subsequently, structures of olivine, epidote, tourmaline, enstatite, hornblende and biotite, representing the major classes of silicate minerals, were developed and their weathering simulated. Neoformation of layer silicates was also picturised. The method presented here can be extended to any clay mineral and their weathered products as also neoformation routes under any given situation. Top |