一、引言X 射线结晶学从二十年代以来,一直作为物质结构研究中的一个重要工具。但是,随着科学技术的发展,越来越要求对像无定形材料、多相催化剂、催化剂载体及化学性质不稳定的原子簇等的结构有精确的了解。而对这些一般难以获得单晶的物质,X 射线结晶学所能提供的结构信息是极其有限的。近年发展起来的新 I. INTRODUCTION X-ray crystallography has been an important tool in the study of material structure since the 1920s. However, with the development of science and technology, there is an increasing demand for an accurate understanding of the structure of amorphous clusters, heterogeneous catalysts, catalyst supports and chemically unstable clusters. For these generally difficult to obtain single crystal material, X-ray crystallography can provide structural information is extremely limited. In recent years developed new