화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals, Vol.383, 81-97, 2002
Morphology of new (P2(1)/n) metastable anthracene modification crystals, grown from the vapor phase
The morphology of the vapor-grown crystals of a new metastable anthracene modification (that crystallizes in the monoclinic space group P2(1)/n with a = 8.553(2), b = 6.021(1), c = 22.334(4) Angstrom, beta = 124.54(3)degrees, and four molecules per unit cell) was determined from the X-ray single crystal orientation data and optical reflection goniometry measurements. In the standard space group P2(1)/c, the crystals of this new phase possessed a rhomboidal tabular habit with two major {002} faces oriented in [001] direction, and twelve lateral faces of {11(3) over bar}, {111}, {100}, and {102}. This morphology differs nearly fully from that observed for the crystals of a long-known parent anthracene phase (P2(1)/a) grown under the same conditions. The experimental morphologies of both crystal phases were compared with those predicted from the periodic band chain (PBC) theory of Hartman and Perdok. Moreover, the melting point for this new metastable anthracene phase, equal to 215.1degreesC, was determined with help of a differential scanning calorimeter.