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Crystal Structure of 2-Phenylazulene

Naturevolume 192pages863864 (1961) | Download Citation



AFTER a long controversy, the space group of azulene is now apparently established as the centro-symmetrie P21/a, with two non-centro-symmetric molecules in the unit cell1,2, a result which leads to a disordered structure in which successive azulene molecules in the crystal are reversed in direction at random. Two previously observed cases of random positioning, namely, between chlorine and bromine in p-chlorobromobenzene3 and between methyl and chlorine in 2-amino-4-methyl-6-chloropyrimidine4, involve atoms or groups of comparable size, and are not as surprising as is the case of azulene, where there is a rather large difference in size between the five- and seven-membered rings.

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  1. 1

    Robertson, J. M., Shearer, H. M. M., Sim, G. A., and Watson, D. G., Nature, 182, 177 (1958).

  2. 2

    Sim, G. A., Acta Cryst., 13, 850 (1960).

  3. 3

    Klug, A., Nature, 160, 570 (1947).

  4. 4

    Clews, C. J. B., and Cochran, W., Acta Cryst., 1, 4 (1948).

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  1. Chemistry Department, University of Southern California, Los Angeles, 7

    • B. D. SHARMA
    •  & J. DONOHUE


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