V-SPER play online

Build and observe to come true with figures of repulsion, geometry, angles.

V-SPER, free application, is a support for the teaching of the VSPER theory (Valence Shell Electron Pair Repulsion). This theory makes it possible to predict the geometry of molecules from the sole electrostatic repulsion of valence electron pairs.
It is based on the Lewis model of distribution of the valence electrons of the atoms concerned. The latter is a prerequisite to take full advantage of V-SPER. The molecule is denoted AXnEm. The atoms (or portions of molecules) linked to the central atom A are denoted X (n: number of X, whether they are linked by single or multiple bonds).
The non-bonding electron pairs belonging to the central atom A and not being involved in bonds are denoted E (m: number of E). V-SPER allows to build simple and 3D objects (molecules) and to display the repulsion figure in blue (FigREP), the molecular geometry in yellow (Geom) as well as the angles.
Some angles are just modeled and do not always correspond to experimentally measured angles, such as the relative lengths of single or multiple bonds