âSorry for the paucity of posts over the past few days but I'm in a state of upheaval known as âjob changeâ.â âThere is no scheme in all these projects to solve the paucity of clean, safe drinking water.â âThe paucity of these qualities in the present Republic would stagger them.â
Benzene is the archetypical aromatic compound. It is planar, bond angles=120Âº, all carbon atoms in the ring are sp2 hybridized, and the pi-orbitals are occupied by 6 electrons. The aromatic heterocycle pyridine is similar to benzene, and is often used as a weak base for scavenging protons.
It has four electron pairs, and thus VSEPR predicts a tetrahedral geometry with 109.5Â° bond angles. However, one of the four is a lone pair, taking up more space, and so the three bonding electron pairs are squeezed together slightly.The experimentally measured HâNâH bond angle in ammonia is, in fact, 107.3Â°.efinement of the VSEPR Model Lone electron pairs, which are not confined between nuclei, use more space than do bonding pairs, which are restricted to the narrow space between their two nuclei. The âfatâ lone pairs distort the ideal electron-pair geometries predicted by VSEPR theory.