Skip to main content Accessibility help

The Normal Paraffins Revisited

  • R. D. Heyding (a1), K. E. Russell (a1), T. L. Varty (a1) and D. St-Cyr (a2)


The low temperature modifications of the normal paraffins n-CnH2n+2crystallize in three groups (Broadhurst, 1962). The structure is triclinic for n even, 6 < n < 26 (Muller and Lonsdale, 1948; Nyburg and Luth, 1972); orthorhombic for n odd, 11 < n < 39 (Smith, 1953; Teare, 1959); and monoclinic for n even, 28 < n < 36 (Shearer and Vand, 1956). In all of these structures the hydrocarbon chains are linear and in trans configuration. The chains are parallel to one another, the terminal methyl groups forming the surfaces of lamella which are more or less perpendicular to the chain axis. For n < ca.36, it is apparently the interlamellar interaction between end methyl groups which dictates the symmetry. For longer chains the structure is usually orthorhombic and comparable to the structure of highly crystalline polyethylenes. Chains do not fold (as they undoubtedly do in polyethylenes) unless n is greater than 102 (Bidd and Whiting, 1985; Ungar and Keller, 1986).

The several crystal forms differ in the manner in which the nearest neighbor chains are related to one another. In the triclinic lattices the packing is such that a triclinic sublattice containing one methylene group is evident. In the other modifications the sublattice is orthorhombic and contains four methylene groups. If the overall symmetry is orthorhombic the long chain axes are perpendicular to the interlamellar surface; the x and y translations, perpendicular to the long axis, are common to both cells. If the nearest neighbor chains are displaced by two or four methylene groups along the chain axis, overall monoclinic symmetry results (Sullivan and Weeks (1970)).



Hide All
Appleman, D.E., and Evans, H.T.(1973). U.S. Geol. Survey Computer Contribution 20. U.S. Natl. Tech. Information Service DocPB2-16188.
Asano, T.(1983). Polymer Bull.(Berlin), 10, 547.
Bidd, I.L., and Whiting, M.C.(1985). J. Chem. Soc, Chem. Comm., 543.
Broadhurst, M.G.(1962). J. Res. Nat. Bur. Stand. 66A, 241.
Bunn, C.W.(1939). Trans. Faraday Soc. 35, 482.
Denicolo, I., Doucet, J., and Craievich, A.F.(1983). J. Chem. Phys. 78, 1465.
Doucet, J., Denicolo, I., Craievich, A., and Collet, A.(1981). J. Chem. Phys., 75, 5125.
Doucet, J., Denicolo, I., Craievich, A., and Germain, C., (1984) J. Chem. Phys., 80, 1647.
Doucet, J.and Dianoux, A.J., (1984). J. Chem. Phys. 81, 5043.
Ewan, B., Strobl, G.R., and Richter, D., (1980). Faraday Discuss. Chem. Soc., 69, 19.
Gabe, E.J., and Gainsford, G.(1982). Division of Chemistry, National Research Council of Canada. Private Communication.
Jones, R.N., and Pitha, J.(1976). Computer Programs for Infrared Spectrophotometry. Chap. X. National Research Council of Canada, Bulletin 12. 2ndEd.
Kelusky, E.C., Smith, I.C.P., Elliger, C.A., and Cameron, D.G.(1984). J. Am. Chem. Soc., 106, 2267.
Maroncelli, M., Strauss, H.L., and Snyder, R.G., (1985). J. Chem. Phys. 52, 2811.
Nakamura, T., Sameshima, K., Okunaga, K., Yoshitaka, S., and Sato, J.(1989). Powder Diffraction, 4, 9.
Nyburg, S.C., and Luth, H.(1972). Acta Crystallog. B28, 2992.
Nyburg, S.C., Pickard, F.M., and Norman, N.(1976). Acta Cryslallogr., B32, 2289.
Nyburg, S.C., and Potworowski, J.A., (1973). Acta Crystallogr., B29, 347.
Shearer, H.M.M., and Vand, V.(1956). Acta Crystallogr., 9, 379.
Smith, A.E.(1953). J. Chem. Phys., 21, 2229.
Strobl, G., Ewan, B., Fischer, E.W., and Piesczek, W., (1974). J. Chem. Phys., 61, 5257. (See also Strobl et al.(1980), Faraday Discuss. Chem. Soc. 69, 19, and papers cited therein.)
Teare, P.W.(1959). Acta Cryslallogr., 12, 294.
Ungar, G.(1983). J. Phys. Chem., 83, 689.
Ungar, G., and Keller, A.(1986). Polymer 27, 1835.


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed