期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1974
卷号：71
期号：11
页码：4348-4351
DOI：10.1073/pnas.71.11.4348
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Serendibite with very similar analyses is known from Ceylon and New York. The triclinic cell of symmetry P[unk] and volume 670.9 A3 contains 2Ca1.64Mg2.64Fe0.27IIAl4.64B1.66Si3O20, with 14 metal atoms and 20 oxygen atoms in the asymmetric unit. It was solved by the "direct" method of transforming the ordinary three-dimensional Patterson function into an approximation of the electron density by using conjugate peaks and minimum functions, followed by successive Fourier syntheses and least-squares refinement to R = 7.1%. This new structure is composed of interrupted brucite-type layers which form an octahedral framework, and winged single chains of tetrahedra. The structure has units of similar, but not identical, geometry to those of the minerals sapphirine and aenigmatite, and these similar units are assembled in a different way.
关键词：Patterson function ; conjugate peaks ; minimum function ; winged single chain of tetrahedra
