Why benzene molecule is planar

Problem 6. Problem 7. Problem 8. Problem 9. Problem Video Transcript this question asked. Numerade Educator. Liquids - Intro A liquid is a nearly incompressible fluid that conforms to the shape of its ….

Why isn't cyclohexane a planar molecule? Explain benzene's structure and how it makes the molecule unusually sta….

Explain why the concept of delocalized molecular orbitals is essential to an…. Benzene i…. Why is polarity a key connection between the structure of a molecule and its…. Why are aromatic molecules stable? The presence of the delocalized electrons makes benzene particularly stable. Benzene resists addition reactions because those reactions would involve breaking the delocalization and losing that stability.

Benzene is represented by this symbol, where the circle represents the delocalized electrons, and each corner of the hexagon has a carbon atom with a hydrogen attached. Because of the aromaticity of benzene, the resulting molecule is planar in shape with each C-C bond being 1. You might ask yourselves how it's possible to have all of the bonds to be the same length if the ring is conjugated with both single 1.

The delocalisation of the electrons means that there aren't alternating double and single bonds. It is planar because that is the only way that the p orbitals can overlap sideways to give the delocalised pi system.

This is accounted for by the delocalisation. As a general principle, the more you can spread electrons around - in other words, the more they are delocalised - the more stable the molecule becomes. The extra stability of benzene is often referred to as "delocalisation energy". With the delocalised electrons in place, benzene is about kJ mol -1 more stable than it would otherwise be.

If you added other atoms to a benzene ring you would have to use some of the delocalised electrons to join the new atoms to the ring. That would disrupt the delocalisation and the system would become less stable.

Since about kJ per mole of benzene would have to be supplied to break up the delocalisation, this isn't going to be an easy thing to do. The hexagon shows the ring of six carbon atoms, each of which has one hydrogen attached. You have to know that - counting bonds to find out how many hydrogens to add doesn't work in this particular case.

The circle represents the delocalised electrons. It is essential that you include the circle. If you miss it out, you are drawing cyclohexane and not benzene. If this is the first set of questions you have done, please read the introductory page before you start. The asymmetry of the PES around the crystal position cf.

It is evident that the area with the most positive ESP i. The Bi atom is thus not directly accessible for benzene in this complex. The benzene molecule cannot move closer due to the steric clashes with the NMe 2 moieties; the respective stabilization energy is only about 4.

Here, the equilibrium distance is shorter about 3. The crystal position of the benzene molecule is again at the minimum of the potential energy curve. The computed data show that the interactions of both complexes are of similar nature with most important dispersion energies followed by electrostatic and induction energies.

Although there is a plethora of procedures for crystal structure prediction and calculation based on ab initio methods or cooperation of X-ray, NMR and theoretical methods is reported 15 but to the best of our knowledge only one paper deals with a post-treatment of disordered small molecules.

It is clear that the refinement of the primary-disorder carbon atom resulting in a single planar benzene ring would be wrong because of the omissions of several according to X-ray data quality and the resolution of the Fourier electron density map positions of the benzene molecule which pendulates one carbon atom is rigid and the rest of the electron density attributable to the carbon atoms migrates horizontally , oscillates in a slight vertical motion and rotates around C 6 axis between the two bismuth atoms.

This is probably caused by the fact that the only rigid carbon atom of the benzene molecule is found in the special crystallographic position; moreover, it is influenced by two types of interactions with both Bi atoms, which pull the electron density of the ring into different directions. It may be concluded that the QM calculations of the studied intermolecular complexes clearly demonstrate an almost free motion of the benzene molecule between the two Bi atoms, and the bent structure of benzene obtained by X-ray crystallography is in fact a superimposition thermal average of the ensemble of thermally populated benzene structures in the complex studied.

DOI: Received 5th November , Accepted 6th November Abstract The non-planarity of the benzene moiety in the crystal of a chelated bismuth III heteroboroxine complex was not supported by DFT-D quantum chemical calculations.