Contains sufficient parts to make eight atomic models. Each model is an example of the different orientations of the bonds and cover coordination numbers 1 to 6. Line pairs are repressented by brown spheres or brown pear shaped parts. The letter is useful as pronated models of NH4+ and H30+ may be built thus demonstrating Acid/Base theory. Sphere-1 carbon (IV), 1 oxygen (IV), 1 nitrogen (IV), 1 surphur (VI), 1 phosphorus (V), 1 chorine (IV), 1 boron (III), 1 metal (berylium (II), 7 chorine (I), 6 fluorine (I), 13 hydrogen, 6 circular lone pair orbitals, 6 pear shaped lone pair orbitals. Links-26 gray pear shaped sigma bonds, 6 short links (to be used with circular lone pairs).