Orthorhombic packing

Removal of the carboxyl group from a BS molecule leaves heneicosane (C21) which exhibits no liquid-crystalline phase, but does form two layered solid phases in which the C21 molecules are fully extended with the molecular axes normal to the layer planes [320]. In the higher temperature solid (Phase II), the molecules are hexagonally packed within and execute hindered rotations about their long axis. In the lower temperature solid (Phase I), the rotational motions are damped and the molecules are orthorhombically packed within a layer. Gauche defects in the preferred al -transoid conformations occur more frequently near layer ends than near the middle of layers... 

Chen, YL. and Wiedmann, T.S. (1996). Human stratum corneum lipids have a distorted orthorhombic packing at the surface of cohesive failure, J. Invest. Dermatol, 107 15-19. 

The above permeabilities roughly constitute the averages of the values obtained along the various directions considered in the orthorhombic packings, while the conductivities are closer to the smallest conduction. 

The influence of the double layer thickness in these random packings was also investigated by Coelho et al. [9] and follows the same trends as those calculated for orthorhombic packings. 

FIG. 9 Reduced coupling coefficients x jl K and jX K as functions of kA for all the configurations studied in Sec. VI. Data are for regular packings ( ), orthorhombic packings (O) random packings ( ), and reconstructed sandstones (+). Theoretical results from Eq. (93a) with A = y8/3/i (solid line), Eq. (93b) with A = R (dashed line), and Eq. (100) (dotted line). (+) Experimental results for montmorillonite from Refs. 17 and 44-46. 

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