An Excel Spreadsheet for Predicting the Geometries of Chemical Species

The use of a geometry predictor (GP), which is programmed on an Excel spreadsheet, is described. A user makes numerical entries for a chemical formula (i.e., its central atom, other atoms or groups, and charge, if any), and the GP displays the number of electron domains and hybridization of the central atom as well as the geometry of the species. It also shows the central atom’s number of hybrid orbitals, ligands, and lone pairs of electrons, when present, and it indicates when the species is a radical. The GP finds geometries ranging from linear to octahedral for covalent compounds, cations, anions, or radicals composed of main-group elements. The results are identical to those found by students using the VSEPR methodology. Extra features include hyperlinks that connect the geometry found by the GP to drawings and to electronically generated models having that geometry. A downloadable folder that contains the GP and its associated files is available. The GP is freeware that students can use in concert with their course materials to visualize and learn molecular geometries.