用直接法处理由重原子引起的四重解

溴化五味子醇乙C₂₃H₂₇O₇Br的单晶体属P2₁2₁2₁空间群,每个晶胞含4个分子。由于Br原子的y和z坐标都非常接近于1/4,无论用重原子法还是用Patterson法,相应于每一个轻原子的位置都可能出现四种不同的解,因而正常的分析无法进行下去。用作者之一提出的方法顺利地消除了重原子引起的赝解,从而求出正确的结构。关键词：

ELIMINATION OF THE FOUR-FOLD AMBIGUITIES DUE TO THE ARRANGEMENT OF HEAVY ATOMS BY MAKING USE OF THE DIRECT METHOD

Single crystals of 4-Bromowuweizichun B, C₂₃H₂₇O₇Br, belong to the space group P2₁2₁2₁ with four molecules per unit cell. Since both the Y and Z parameters of the bromine atom are close to 1/4, either the heavy atom method or the Patterson method would lead to a four-fold ambiguity for each light atom. Consequently the structure analysis could not proceed by the usual way. By making use of the method proposed by one of the authors, the ambiguity was easily resolved and the correct structure obtained.