Boron, Nitrogen and Chlorine Trifluorides

Most of the principles by which AB3 molecules, such as BF3, NF3 and C1F3, are treated have been dealt with in previous sections. For this reason, their treatments are presented in a relatively concise fashion with only additional points being stressed. 

In valence bond terms the bonding consists of three a bonds and one dative or coordinate n bond. The latter are electron pair bonds between two atoms in which both electrons originate from one of the participating atoms. 

Q (i) Take the 2p orbitals of three fluorine atoms pointing towards the centre of an equilateral triangle and classify their combinations in terms of the Dih point group, (ii) Classify the three 2p orbitals which are perpendicular to the trigonal plane. 

A (i) The results of estimating the number of the 2p fluorine ligand orbitals in the equilateral plane that are unaffected by the symmetry operations of the Dih point group are  

This representation of the group orbitals may be converted to its constituent irreducible representations by considering that it is likely that they are identical with the representations to which the 2s and 2p atomic orbitals of the boron atom belong. The subtraction of the characters of the a, representation gives the result  

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