ISSN:
1600-5724
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
If the atoms in a unit cell are not almost randomly distributed difficulties may arise in the normal application of direct methods. Structural information can be taken into account mainly by modification of the probability distribution of the E values or by modification of the E values themselves. A straightforward method involving the second possibility, applied successfully to the solution of two noncentrosymmetric steroid structures, is described in this paper. The modified E values are calculated by the formula |Em(hkl)| = [|Eobs(hkl)|2 - c|Efrag(hkl)|2 ]1/2 with Em(hkl) = modified E value, Eobs(hkl) = observed E value, Efrag(hkl) = theoretical E value calculated with coordinates of a correctly oriented molecular fragment.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0567739482001776
