Letter | Published:

Anomalous Thermal Expansion of the Short Intermolecular Bond in para-Nitro-aniline

Naturevolume 166pages6970 (1950) | Download Citation



A RECENT determination of the detailed crystal structure of para-nitro-aniline has revealed an un usually short distance of approach (2.66 A.) between the oxygen atom of an NO2 group of one molecule and one of the carbon atoms of the aromatic nucleus on a proximate molecule1. This suggests special forces between these two atoms, the attraction of which appears to be intermediate between that in a covalent bond, and that due solely to Van der Waals' forces, and may be electrostatic in origin.

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  1. Department of Chemistry, Queen's University, Belfast

    • P. J. McKEOWN
    • , A. R. UBBELOHDE
    •  & I. WOODWARD


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