Chemistry Reference
In-Depth Information
In a later work [21] it was suggested to consider various types of superclusters [M
14
F
68
]
and to name their extreme compositions [M
8
{R
6
F
36
}F
32
] as octacubic cluster and
[R
8
{M
6
F
36
}F
32
] as inverted octacubic cluster (Figure 14.14). In the M
1
x
R
x
F
2
þ
x
solid
solutions, the formation of supercluster with variable R
3
þ
dopant content [M
14
n
R
n
F
68
]is
possible. Such clusters have a size of around 1 nm.
F
(8
c
)
[
M
6
F
32
]
F
int(48
i
)
[
M
6
F
36
]
[
R
6
F
36
]
R
3+
[
M
2+
]
M
2+
R
3+
[
M
8
{
R
6
F
36
}F
32
]
Octacubic cluster
[
R
8
{
M
6
F
36
}F
32
]
Inverted
octacubic cluster
Figure 14.14 Superclusters in the M
1x
R
x
F
2þx
solid solutions. (Reprinted with permission from
[21] Copyright (2008) Pleiades Publishing Inc.)
The model of the supercluster formation from cuboctahedral anion clusters and their
surroundings of cationic polyhedra is quite applicable to other types of anionic clusters.
The formation of a nonstoichiometric fluorite-like solid solution and the coexistence
of various cluster types (cuboctahedral and tetrahedral) in it is well illustrated in
Figure 14.15)[7].
