Half-Crystal Energy and Enthalpy of Sublimation of Diuron: 3-(3,4-Dichlorophenyl)-1,1-dimethylurea
The enthalpy of sublimation of diuron, 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea, C9H10ON2Cl2, was measured at 393 K using a Tian–Calvet calorimeter. The corrected experimental value ΔsubHmο (298K) = 133.87 (74) kJ mol−1 was then compared to the half‐crystal energy Ek. This energy was calculated from...
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Published in | Journal of applied crystallography Vol. 30; no. 5-1; pp. 527 - 531 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
5 Abbey Square, Chester, Cheshire CH1 2HU, England
International Union of Crystallography
01.10.1997
Blackwell |
Subjects | |
Online Access | Get full text |
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Summary: | The enthalpy of sublimation of diuron, 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea, C9H10ON2Cl2, was measured at 393 K using a Tian–Calvet calorimeter. The corrected experimental value ΔsubHmο (298K) = 133.87 (74) kJ mol−1 was then compared to the half‐crystal energy Ek. This energy was calculated from structural data using the `consistent valence force field', which consists of a 6–12 Lennard–Jones potential and a Coulomb term. The disagreement between ΔsubHmο (298K) and Ek = 152.6 kJmol−1 is about 14%. It can be partially attributed to the inaccuracy of the atomic coordinates of the crystal structure and to the charges of the force field. For simple molecules such as normal octadecane (n‐C18H38), hexanedioic acid (C6H10O4), diphenylmethanone (C13H10O) and anthracene (C14H10), the agreement is very good, about 3%. |
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Bibliography: | istex:98D7B7DA5BA29DC04AC472EC42D716D06B71A1A1 ark:/67375/WNG-5JJ8DL1N-6 ArticleID:JCRVI0067 |
ISSN: | 1600-5767 0021-8898 1600-5767 |
DOI: | 10.1107/S0021889896014501 |