Combinatorial-topological type of atomic VDP can be used to analyze atomic coordination polyhedron (CP). A small distortion of a polyhedron often change its combinatorial-topological type, therefore CP should be simplified to determine its stable shape.
In particular, contraction of shortest edges can be used for simplification of combinatorial-topological type. The edge size can be estimated using the value of the angle a based on this edge with top in the VDP central atoms. The dependence of the frequency of CP combinatorial-topological types for potassium atoms [1] in chloride environment vs a is shown in figure.
Figure. Dependence of the frequency (in percents) vs a (in degrees).
Obviously the most stable CP combinatorial-topological types of the optimal polyhedra of the well known Gillespie model [2]. The examples of CP topological types for a = 30? degrees and corresponding crystal structures are given in table. Some topological types and crystal structure examples are shown in the table for a = 30 degrees.
Classification of KCln CPs by their combinatorial-topological types. Combinatorial-topological types of optimal polyhedra are colored.
|
Polyhedron
|
CP shape
|
Compound Refcode |
||
|
KCl6
|
Trigonal prism |
6/5-1
|
3/6
|
K4Nb6Cl18 {41118} |
| Pentagonal pyramid |
6/6-1
|
3/4 4/2
|
K2ZnCl4 {50087} | |
| Distorted octahedron |
6/7-1
|
3/2 4/4
|
C2H4Cl3PtK {KCEYPT} | |
| Octahedron |
6/8-1
|
4/6
|
KCl {22156} | |
|
KCl7 |
One-cap trigonal prism |
7/7-1
|
3/4 4/3
|
K(2) K2CoCl4 {661} |
|
7/9-1
|
3/1 4/5 5/1
|
K(2) K2ZnCl4 {66515} | ||
| One-cap octahedron |
7/8-1
|
3/2 4/5
|
KDy2Cl7 {37007} | |
| Pentagonal bipyramid |
7/10-1
|
4/5 5/2
|
K2Tc2Cl6 {63512} | |
|
KCl8
|
Square prism |
8/6-1
|
3/8
|
K2PdCl4 {39852} |
| Square antiprism |
8/8-1
|
3/4 4/4
|
KTlCl4 {14105} | |
|
8/9-1
|
3/2 4/6
|
K(15) K2ZnCl4 {66515} | ||
|
8/10-1
|
4/8
|
KSm2Cl5 {65167} | ||
|
8/10-2
|
3/1 4/6 5/1
|
K2InCl5(H2O) {200970} | ||
|
8/11-1
|
4/6 5/2
|
K2PuCl5 {202525} | ||
| One-cap pentagonal bipyramid |
8/8-2
|
3/4 4/4
|
K2CoCl4 {660} | |
|
8/9-2
|
3/2 4/6
|
K(11) K2ZnCl4 {66515} | ||
|
8/10-3
|
3/2 4/4 5/2
|
K(4) K2ZnCl4 {66515} | ||
|
Trigonal dodecahedron |
8/12-1
|
4/4 5/4
|
K(5) K2CoCl4 {660} | |
|
KCl9 |
One-cap
square antiprism |
9/9-1
|
3/4 4/5
|
K2MgCl44 {4035} |
|
9/10-1
|
3/2 4/7
|
K(La5(C2) )Cl10 {400813} | ||
|
9/11-1
|
3/1 4/7 5/1
|
K2Tc2Cl6 {63512} | ||
|
9/11-3
|
3/2 4/5 5/2
|
K2Pr4Cl9O2 {400004} | ||
|
9/11-4
|
3/1 4/7 5/1
|
K3IrCl6H2O {38433} | ||
|
9/11-6
|
4/7 5/2
|
K(2) K3((SnCl3)IrCl5) {69143} | ||
|
9/12-2
|
4/7 5/2
|
K2FeCl5H2O {30321} | ||
|
9/13-2
|
4/5 5/4
|
K(3) K3IrCl6 {63454} | ||
| Three-cap trigonal prism |
9/9-2
|
3/4 4/5
|
K2(RuCl5(NO)) {72617} | |
|
9/12-1
|
3/1 4/5 5/3
|
K(Ce5(C2))Cl10 {400815} | ||
|
9/11-5
|
4/9
|
K3Mo2Cl9 {202298} | ||
|
9/13-1
|
4/5 5/4
|
KAlCl4 {1704} | ||
| One-cap square prism |
9/9-3
|
3/5 4/3 5/1
|
KAuCl4 {73080} | |
|
9/10-2
|
3/2 4/7
|
K(2) CCl5OK2(H2O) {YIJYUL01} | ||
|
9/11-2
|
3/2 4/5 5/2
|
KAuCl4 {2607} | ||
| Nonahedron |
9/10-3
|
3/2 4/7
|
KNiCl3 {10508} | |
|
KCl10 |
Cube with two centered neighboring faces |
10/10-1
|
3/4 4/6
|
K(2) KMoOCl4 {410722} |
|
10/11-1
|
3/2 4/8
|
K2MoOCl5 {28215} | ||
|
10/13-2
|
3/1 4/6 5/3
|
KGa2Cl7 {12} | ||
| Cube with two centered opposite faces |
10/11-2
|
3/2 4/8
|
KZr6Cl15C {202462} | |
| Decahedron |
10/13-1
|
4/9 6/1
|
K2PuCl6 {202526} | |
|
KCl11
|
Three-cap square prism |
11/13-2
|
4/11
|
K(2) KNbCl6 {73155} |
|
KCl12
|
Cubooctahedron |
12/14-1
|
4/12
|
K2MoCl6 {26643} |
| Hexagonal dodecahedron |
12/14-2
|
4/12
|
K2Mn((NbCl)6Cl12) {82102} | |
|
KCl8K6
|
Fedorov’s cubooctahedron |
14/24-1
|
4/6 6/8
|
KCl {61557} |
References
1. E. A. Bikanina, A. P. Shevchenko, and V. N. Serezhkin // Russian Journal of Coordination Chemistry, Vol. 31, No. 1, 2005, p. 68.
2. Gillespie, R.G. and Hargittai, I., The VSEPR Model of Molecular Geometry, Boston: Allyn & Bacon, 1991.