On the crystal structure of the germanium-based cationic clathrates [Ge38.3Sb7.7]I7.44, [Ge38.1P7.9]I8, and [Ge30.5Sn7.7P7.75]I7.88

• Published in: Russian journal of coordination chemistry Vol. 38; no. 3; pp. 192 - 199
• Main Authors: Kirsanova, M. A., Reshetova, L. N., Olenev, A. V., Shevelkov, A. V.
• Format: Journal Article
• Language: English
• Published: Dordrecht SP MAIK Nauka/Interperiodica 01-03-2012
• Subjects: Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Physical Chemistry; Germanium; Clathrate; Germanium Atom; Coordination Chemistry; Band Structure Calculation
• ISSN: 1070-3284; 1608-3318
• DOI: 10.1134/S1070328412030062

Compounds [Ge
38.3
Sb
7.7
]I
7.44
, [Ge
38.1
P
7.9
]I
8
, and [Ge
30.5
Sn
7.7
P
7.75
]I
7.88
with the clathrate type-I structure were synthesized. They crystallize in the cubic space group
with the unit cell parameter
a
= 10.8592(9), 10.4983(12), and 10.7210(10) Å (
Z
= 1), respectively. Their crystal structure represents the germanium(tin)-pnictogen framework, capturing the guest iodine anions in its cavities. All compounds have no vacancies in the host substructure; however, two of them show vacancies in the guest positions. The atomic distribution over the framework sites is of the most interest as it follows trends associated with the relative electronegativities of the atoms composing the framework. The results of the band structure calculations and application of the Zintl counting scheme are also discussed in relation to potential thermoelectric properties.