Structure of Halogen-Bonded Complexes

The complex furan CIF is the only one to contravene these rules. While HCl and HF form a hydrogen bond to the n-pair of oxygen, CIF interacts with the tt-electron density. In other molecules with two potential acceptor sites, the observed geometries give the 

The data in Table 5.1 can be compared with the ka values of the corresponding hydrogen-bonded dimers B- -H—Y [47] by means of Equation 5.2  

These observations indicate that the halogen bond will provide information complementary to that of the hydrogen bond for measuring Lewis basicity quantitatively. 

Many X-ray crystal structures have been reported for halogen-bonded complexes since the first determination in 1954 [5]. In the case of inorganic halogens, the structures of 141 complexes could be found [14] in the October 2002 version of the CSD. They correspond to 219 halogen bonds between the dihalogens I2 (mainly), IBr, ICl, Br2 and CI2, and the B atomic centres C (n), O, S (—S—, C=S, PS), Se (—Se—, C=Se, PSe), N (sp, sp, sp). 

P (sp ) and As (sp ). A statistical investigation [14] of this crystallographic database shows 

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