CRYSTAL CHEMISTRY OF URANYL MOLYBDATES. XI. CRYSTAL STRUCTURES OF Cs2[(UO2)(MoO4)2] AND Cs2[(UO2)(MoO4)2](H2O)

2005 ◽  
Vol 43 (2) ◽  
pp. 713-720 ◽  
Author(s):  
S. V. Krivovichev ◽  
P. C. Burns
Keyword(s):  
Crystal Structures ◽  
Crystal Chemistry

scholarly journals Nets with collisions (unstable nets) and crystal chemistry

2013 ◽  
Vol 69 (6) ◽  
pp. 535-542 ◽  
Author(s):  
Olaf Delgado-Friedrichs ◽  
Stephen T. Hyde ◽  
Shin-Won Mun ◽  
Michael O'Keeffe ◽  
Davide M. Proserpio
Keyword(s):  
Crystal Structures ◽  
Crystal Chemistry ◽  
Barycentric Coordinates ◽  
Real Crystal ◽  
Crystallographic Symmetry

Nets in which different vertices have identical barycentric coordinates (i.e.have collisions) are called unstable. Some such nets have automorphisms that do not correspond to crystallographic symmetries and are called non-crystallographic. Examples are given of nets taken from real crystal structures which have embeddings with crystallographic symmetry in which colliding nodes either are, or are not, topological neighbors (linked) and in which some links coincide. An example is also given of a crystallographic net of exceptional girth (16), which has collisions in barycentric coordinates but which also has embeddings without collisions with the same symmetry. In this last case the collisions are termedunforced.

Crystal structures and electronic properties of Sn3N4 polymorphs synthesized via high-pressure nitridation of tin

CrystEngComm ◽  
2020 ◽  
Vol 22 (20) ◽  
pp. 3531-3538
Author(s):  
Ken Niwa ◽  
Tomoya Inagaki ◽  
Tetsu Ohsuna ◽  
Zheng Liu ◽  
Takuya Sasaki ◽  
...  
Keyword(s):  
High Pressure ◽  
Electronic Properties ◽  
Crystal Structures ◽  
Crystal Chemistry ◽  
Diamond Anvil Cell ◽  
Functional Materials ◽  
Group Iva ◽  
Diamond Anvil ◽  
Laser Heated ◽  
Insight Into

Sn3N4 polymorphs were synthesized via high-pressure nitridation of tin by means of laser-heated diamond anvil cell technique. This implies new insight into the crystal chemistry and functional materials of group IVA nitrides.

Crystal chemistry of zirconosilicates and their analogs: topological classification of MT frameworks and suprapolyhedral invariants

2002 ◽  
Vol 58 (2) ◽  
pp. 198-218 ◽  
Author(s):  
G. D. Ilyushin ◽  
V. A. Blatov
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Crystal Chemistry ◽  
Three Dimensional ◽  
Geometrical Interpretation ◽  
Topological Classification ◽  
Hierarchical Analysis ◽  
Framework Structure ◽  
Coordination Spheres

The first attempt is undertaken to consider systematically topological structures of zirconosilicates and their analogs (60 minerals and 34 synthetic phases), where the simplest structure units are MO6 octahedra and TO4 tetrahedra united by vertices ([TO4]:[MO6] = 1:1–6:1). A method of analysis and classification of mixed three-dimensional MT frameworks by topological types with coordination sequences {N k } is developed, which is based on the representation of crystal structure as a finite `reduced' graph. The method is optimized for the frameworks of any composition and complexity and implemented within the TOPOS3.2 program package. A procedure of hierarchical analysis of MT-framework structure organization is proposed, which is based on the concept of polyhedral microensemble (PME) being a geometrical interpretation of coordination sequences of M and T nodes. All 12 theoretically possible PMEs of MT 6 polyhedral composition are considered where T is a separate and/or connected tetrahedron. Using this methodology the MT frameworks in crystal structures of zirconosilicates and their analogs were analyzed within the first 12 coordination spheres of M and T nodes and related to 41 topological types. The structural correlations were revealed between rosenbuschite, lavenite, hiortdahlite, woehlerite, siedozerite and the minerals of the eudialyte family.

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