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Deviation of the KempsterLipson Law from Linearity
Author(s) -
Fábry Jan,
Kopecký Miloš,
Krupková Radmila
Publication year - 2012
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.201200013
Subject(s) - chemistry , crystallization , linearity , molecule , unit (ring theory) , crystallography , atom (system on chip) , standard deviation , value (mathematics) , thermodynamics , physics , statistics , quantum mechanics , organic chemistry , mathematics , mathematics education , computer science , embedded system
It is shown that the larger organic molecules composed of C, H, N, and O at most crystallizing in the voluminous unit cells tend to be more loosely packed than those that crystallize in the unit cells with small volumes. This is demonstrated by the deviation from the linear relationship ( KempsterLipson law) between the unit‐cell volumes and the sum of the non‐H‐atoms in the unit cell. This deviation can be distinguished from the effect of the varying number of H‐atoms in the described compounds: the ratio of the non‐H‐atom to the H‐atoms converges to a constant value close to 1 towards the large unit‐cell volumes. The proportion of the disordered structures increases towards the large unit‐cell volumes and thus correlates with the less dense packing of the large molecules. The deviation of the KempsterLipson law from linearity can be interpreted as the manifestation of decreasing ability of a crystallization of large molecules.