Layered Atom Arrangements in Complex Materials

Sikafus, K.E. ; R.W.Grimes ; S.M.Corish ; Cleave, A.R. ; M.Tang ; C.R.Stanek ; Uberuaga, B.P. ; J.A.Valdez

Los Alamos National Laboratory

关键词: 36 Materials Science;    Crystal Structure;    Oxidation;    Atoms;    Oxides;   

DOI  :  10.2172/883642
RP-ID  :  LA-14205
RP-ID  :  W-7405-ENG-36
RP-ID  :  883642

美国|英语

来源: UNT Digital Library

【 摘 要 】

In this report, we develop an atom layer stacking model to describe systematically the crystal structures of complex materials. To illustrate the concepts, we consider a sequence of oxide compounds in which the metal cations progress in oxidation state from monovalent (M{sup 1+}) to tetravalent (M{sup 4+}). We use concepts relating to geometric subdivisions of a triangular atom net to describe the layered atom patterns in these compounds (concepts originally proposed by Shuichi Iida). We demonstrate that as a function of increasing oxidation state (from M{sup 1+} to M{sup 4+}), the layer stacking motifs used to generate each successive structure (specifically, motifs along a 3 symmetry axis), progress through the following sequence: MMO, MO, M{sub r}O, MO{sub r/s}O{sub u/v}, MOO (where M and O represent fully dense triangular atom nets and r/s and u/v are fractions used to describe partially filled triangular atom nets). We also develop complete crystallographic descriptions for the compounds in our oxidation sequence using trigonal space group R{bar 3}.