摘要:

AbstractTo describe a structure is to describe chemistry. A description of structure should be simple yet also open up ways for an understanding of complex structures and their properties. Such interrelationships are gained on inspection and discussion of structures in models of interpenetrating partial structures and on application of symmetry operations to whole structures. Transition regions between interpenetrating partial structures can be approximated to periodic minimal surfaces. Chemical reactions,e.g.in ion‐exchange, in heterogeneous catalysis, or in molecular separations in complicated zeolites will take place on these minimal surface

ISSN:0570-0833    

DOI:10.1002/anie.198300693

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198300821

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractMetallic radii, which are obtained from atomic distances in the pure elements, are generally used for the calculation of distances in intermetallic compounds. However, the procedure for using such radii depends on the individual structural type: (a) For high coordination numbers and only slightly differing distances between atoms of the same kind and different atoms, all distances in a structure are proportional to the sum of radii, weighted according to the compositon. Such a “Vegard” relationship for ordered compounds is obeyed by intermetallic compounds with topological close packings, but strictly only if the various kinds of distances are correlatedviasymmetry relationships. For compounds with low coordination numbers the simple sum of radii holds for atoms participating in the shortest bond (e.g.in ionic crystals).‐(b) The number of neighbors determines the size of each atom. It can be shown that the bond strength‐bond length concept, developed for valence compounds, and often dealt with in the literature over the last ten years, is also applicable for alloys. On this basis a formalism is developed which uniformly describes the size of the atoms as a function of the coordination number for both the limiting cases of multiple bonds in molecules and for close packed atomic arrangements in

ISSN:0570-0833    

DOI:10.1002/anie.198300951

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractDuring the last decade modern preparative and structural methods have led to novel and often unexpected oligomeric and polymeric main group element‐sulfur compounds having remarkable bonding and structural properties and reactivities. Examples of important new developments in this area are: the discovery of boron sulfides B8S16and (BS2)nand of ion‐conducting air‐stable thioborates with tetrahedrally coordinated boron; the successful use of boron sulfides in organic and inorganic syntheses; the preparation of different homologous series of molecular polynuclear thio‐ and selenoanions of Ga, In, Si, Ge and Sn, and of new polynuclear sulfide‐ and selenide‐halides of Si and Ge as interesting reagents for inorganic and organic reactions; the synthesis of argyrodite(Ag8GeS6)‐like phases with remarkable solid‐state properties; and the characterization of the SH…S type hydrogen bridge in thiocarbonic acid and thiophosphinic acids, which is of importance for an understanding of certain interactions in sulfur‐co

ISSN:0570-0833    

DOI:10.1002/anie.198301131

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractMolecular metal clusters form a very large and diverse family. They present the opportunity of modeling the intermediates involved in surface mediated catalytic reactions, of providing a source of very reactive mononuclear metal fragments, and of effecting catalytic cycles in which the cluster remains intact. The last mentioned aspect is the subject of this review article. The state‐of‐the‐art of cluster catalysis is critically analyzed. The possibilities offered by molecular metal catalysts of performing catalytic reactions at multimetal atom sites are also disc

ISSN:0570-0833    

DOI:10.1002/anie.198301351

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe complete manuscript of this communication appears in:Angew. Chem. Suppl. 1983, 148. DOI:10.1002/anie.198301480

ISSN:0570-0833    

DOI:10.1002/anie.198301491

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe complete manuscript of this communication appears in:Angew. Chem. Suppl. 1983, 128. DOI:10.1002/anie.198301280

ISSN:0570-0833    

DOI:10.1002/anie.198301501

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe complete manuscript of this communication appears in:Angew. Chem. Suppl. 1983, 114. DOI:10.1002/anie.198301140

ISSN:0570-0833    

DOI:10.1002/anie.198301511

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198301521

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe complete manuscript of this communication appears in:Angew. Chem. Suppl. 1983, 156. DOI:10.1002/anie.198301560

ISSN:0570-0833    

DOI:10.1002/anie.198301531

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY