Layered Atom Arrangements in Complex Materials

181 Pages·2005·6.1 MB·English

LA-14205
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distribution is unlimited.
Layered Atom Arrangements in
Complex Materials
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LA-14205
Issued: April 2006
Layered Atom Arrangements in
Complex Materials
Kurt E. Sickafus
Robin W. Grimes*
Siobhan M. Corish
Antony R. Cleave*
Ming Tang
Chris R. Stanek
Blas P. Uberuaga
James A. Valdez
*Department of Materials, Imperial College of Science, Technology and Medicine,
Prince Consort Road, London SW7 2BP, UK

Contents
Section Name Page
ABSTRACT.............................................................................................................. 1
I.1 Introduction: Background............................................................................... 2
Section I.1 References.................................................................................... 3
I.2 Introduction: The Basic Concepts for Layer Stacking of
Triangular Atom Nets.................................................................................... 4
Section I.2 References.................................................................................... 16
II.1 Representative Crystal Structures: The Simplest Layering Motifs.................. 17
Section II.1 References.................................................................................. 24
II.2 Representative Crystal Structures: Crystallography........................................ 25
Section II.2 References.................................................................................. 26
II.3 Representative Crystal Structures: Layer Sequences....................................... 27
II.4 Representative Crystal Structures: Coordination Polyhedra ........................... 29
III.1 An Expanded Oxidation Sequence: Layering Motifs...................................... 33
III.2 An Expanded Oxidation Sequence: Partially Filled Triangular Atom Nets .... 34
Section III.2 References................................................................................. 39
III.3 An Expanded Oxidation Sequence: Crystallography...................................... 40
III.4 An Expanded Oxidation Sequence: Layer Stacking Sequences ...................... 44
III.5 An Expanded Oxidation Sequence: Lattice Parameters .................................. 65
III.6 An Expanded Oxidation Sequence: Coordination Polyhedra.......................... 66
IV.1 Real Materials: Introduction .......................................................................... 70
IV.2.1 Real Materials: MO Fluorite and M O Antifluorite ...................................... 71
2 2
Section IV.2.1 References.............................................................................. 72
IV.2.2 Real Materials: MX CdCl Structure............................................................. 73
2 2
Section IV.2.2 References.............................................................................. 76
IV.3 Real Materials: M O ................................................................................... 77
7 13
Section IV.3 References................................................................................. 84
IV.4 Real Materials: M O Pyrochlore .................................................................. 85
4 7
Section IV.4 References................................................................................. 94
IV.5 Real Materials: M O .................................................................................... 95
7 12
Section IV.5 References................................................................................. 103
IV.6.1 Real Materials: M O Sesquioxides ............................................................... 104
2 3
IV.6.2 Real Materials: A O Corundum ................................................................... 105
2 3
Section IV.6.2 References.............................................................................. 112
IV.6.3 Real Materials: A O C-Type Bixbyite .......................................................... 113
2 3
Section IV.6.3 References.............................................................................. 122
IV.6.4 Real Materials: A O A-Type Rare Earth ...................................................... 123
2 3
Section IV.6.4 References.............................................................................. 126
IV.6.5 Real Materials: ABO Perovskite .................................................................. 127
3
Section IV.6.5 References.............................................................................. 133
iii
IV.7.1 Real Materials: M O Compounds................................................................. 133
3 4
IV.7.2 Real Materials: AB O Spinel........................................................................ 134
2 4
Section IV.7.2 References.............................................................................. 144
IV.7.3 Real Materials: A Hypothetical M O Compound.......................................... 145
3 4
Section IV.7.3 References.............................................................................. 147
V.1 A Generalized Geometrical Model ................................................................ 148
Section V.1 References.................................................................................. 158
V.2 Potential Applications for Layered Atom Stacking Concepts ......................... 159
Section V.2 References.................................................................................. 170
VI. Conclusions .................................................................................................. 171
List of Tables
Table I.2-1............................................................................................................... 12
Table II.2-1.............................................................................................................. 25
Table II.2-2.............................................................................................................. 26
Table II.3-1.............................................................................................................. 28
Table III.3-1............................................................................................................. 40
Table III.4-1............................................................................................................. 44
Table III.4-2............................................................................................................. 47
Table III.4-3............................................................................................................. 55
Table III.4-4............................................................................................................. 56
Table III.4-5............................................................................................................. 64
Table IV.2.1-1.......................................................................................................... 71
Table IV.3-1............................................................................................................. 77
Table IV.3-2............................................................................................................. 78
Table IV.3-3............................................................................................................. 79
Table IV.4-1............................................................................................................. 86
Table IV.4-2............................................................................................................. 90
Table IV.4-3............................................................................................................. 94
Table IV.5-1............................................................................................................. 96
Table IV.5-2............................................................................................................. 97
Table IV.5-3............................................................................................................. 98
Table IV.5-4............................................................................................................. 102
Table IV.6.2-1.......................................................................................................... 105
Table IV.6.2-2.......................................................................................................... 107
Table IV.6.2-3.......................................................................................................... 112
Table IV.6.3-1.......................................................................................................... 114
Table IV.6.3-2.......................................................................................................... 117
Table IV.6.3-3.......................................................................................................... 118
Table IV.6.4-1.......................................................................................................... 123
Table IV.6.4-2.......................................................................................................... 124
iv
Table IV.6.4-3.......................................................................................................... 126
Table IV.6.5-1.......................................................................................................... 128
Table IV.6.5-2.......................................................................................................... 129
Table IV.6.5-3.......................................................................................................... 131
Table IV.7.2-1.......................................................................................................... 135
Table IV.7.2-2.......................................................................................................... 137
Table IV.7.2-3.......................................................................................................... 139
Table IV.7.3-1.......................................................................................................... 146
List of Figures
Figure I.2-1.............................................................................................................. 4
Figure I.2-2.............................................................................................................. 6
Figure I.2-3.............................................................................................................. 7
Figure I.2-4.............................................................................................................. 10
Figure II.1-1............................................................................................................. 18
Figure II.1-2............................................................................................................. 19
Figure II.1-3............................................................................................................. 21
Figure II.1-4............................................................................................................. 23
Figure II.1-5............................................................................................................. 24
Figure II.4-1...................................................................................................... 29–30
Figure III.2-1............................................................................................................ 35
Figure III.2-2............................................................................................................ 36
Figure III.2-3............................................................................................................ 38
Figure III.4-1............................................................................................................ 57
Figure III.4-2..................................................................................................... 58–63
Figure III.6-1............................................................................................................ 67
Figure IV.2.2-1........................................................................................................ 74
Figure IV.2.2-2................................................................................................. 75–76
Figure IV.3-1.................................................................................................... 81–83
Figure IV.4-1........................................................................................................... 87
Figure IV.4-2........................................................................................................... 88
Figure IV.4-3........................................................................................................... 93
Figure IV.5-1........................................................................................................... 100
Figure IV.5-2........................................................................................................... 101
Figure IV.6.2-1........................................................................................................ 109
Figure IV.6.2-2................................................................................................. 110–111
Figure IV.6.3-1........................................................................................................ 115
Figure IV.6.3-2........................................................................................................ 116
Figure IV.6.3-3........................................................................................................ 119
Figure IV.6.3-4........................................................................................................ 121
Figure IV.6.4-1........................................................................................................ .125
Figure IV.6.5-1........................................................................................................ .130
v
Figure IV.6.5-2........................................................................................................ 132
Figure IV.7.2-1........................................................................................................ 136
Figure IV.7.2-2................................................................................................. 140–143
Figure IV.7.3-1........................................................................................................ 147
Figure V.1-1...................................................................................................... 149–152
Figure V.1-2............................................................................................................. 154
Figure V.2-1...................................................................................................... 159–160
Figure V.2-2............................................................................................................. 162
Figure V.2-3............................................................................................................. 163
Figure V.2-4............................................................................................................. 164
Figure V.2-5............................................................................................................. 166
Figure V.2-6............................................................................................................. 167
Figure V.2-7............................................................................................................. 168
vi
Layered Atom Arrangements in Complex Materials
Kurt E. Sickafus,1 Robin W. Grimes,2Siobhan M. Corish,1 Antony R. Cleave,2

Chris R. Stanek,1 Blas P. Uberuaga,1 and James A. Valdez1
1Materials Science and Technology Division, Los Alamos National Laboratory,
Los Alamos, NM 87545, USA
2Department of Materials, Imperial College of Science, Technology and Medicine,
Prince Consort Road, London SW7 2BP, UK
ABSTRACT
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 (M1+) to tetravalent (M4+). 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 M1+ to M4+), 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 O, MO O , MOO (where M
r r u
s s v
and O represent fully dense triangular atom nets and r and u are fractions used to
s v
describe partially filled triangular atom nets). We also develop complete crystallographic
descriptions for the compounds in our oxidation sequence using trigonal space group R3 .
§ S. Iida, “Layer Structures of Magnetic Oxides,” J. Phys. Soc. Japan 12 (3) 222–233
(1957)
Abstract 1
I.1 Introduction: Background
Much has been written regarding layered atom descriptions for crystalline solids. The
subject is critical to many areas of crystallography, e.g., to describe polytypism and
polysomatism, phenomena observed in numerous minerals and ceramics (see, for
instance, [1,2]). One of the most noteworthy treatises on layer descriptions for oxides was
published by Shuichi Iida in 1957 [3]. Iida introduced a graphical technique to subdivide
triangular nets of atoms (often referred to as triangular Ising nets [4]) into subnets that
mimic classic atomic arrangements such as the honeycomb lattice and the now famous
kagome lattice [5].1,2 Iida demonstrated the efficacy of these subnets by providing simple
descriptions for atomic arrangements in some exceptionally complex crystalline oxides. It
is worth noting that while Iida was trying to understand magnetic properties, there are
many more uses for his ‘layer’ model.
The purpose of this report is to expand the layering concepts first proposed by Iida and to
formalize the crystallography underlying Iida’s models. In this presentation, we will also
introduce a new two-dimensional sublattice that Iida discounted in his original treatise.
We will demonstrate the methodology underlying our layered atom concepts by
considering a hypothetical oxidation sequence in a metal.

1 Kagome means, crudely, “woven basket” in Japanese. Mamoru Mekata published a recent letter in Physics Today [5]
where he credited Kodi Husimi of Osaka University with introducing the descriptor kagome lattice to describe a new
antiferromagnetic lattice he observed in a star-to-triangle transformation of a honeycomb lattice. This appellation first
made print in 1951 in a paper by Itiro Syôzi, Husimi’s colleague [6].
2 The use of the term “lattice” in this context is a misnomer. There are only five two-dimensional (plane) lattices [7],
i.e., Bravais lattices, and these do not include the honeycomb or kagome lattices referred to here. However, we will
(somewhat regrettably) hereafter perpetuate the terms “honeycomb lattice” and “kagome lattice,” as these are more or
less accepted nomenclature in both past and present literature.
2 I.1 Introduction: Background