The three-dimensional arrangement of the atoms that make up a molecule is molecular geometry. It describes the overall molecular shape, bond length, bond angle, torsional angle and all other geometric parameters to determine the location of each atom. Molecular structure prediction based on VSPER. VSPER predicts electron clouds that will be oriented on atoms in such a way as to minimize interaction and therefore, pair electrons as far as possible. Molecular geometry affects several properties of materials including reactivity, polarity, phase of matter, color, attractiveness and biological activity . In 1939, in a reading, Nevil Sidgwick and Herbert Powell of the University of Oxford proposed the concept of a relationship between molecular geometry and the number of valence electron pairs. This definition was refined into a more detailed theory in 1957 between Ronald Gillespie and Ronald Sydney of University College London, who were able to choose between a variety of other alternative geometries.