A simple approach for selective crystal growth of Na8Si46 and Na24Si136

Published

February 10, 2011

Author(s)

Winnie K. Wong-Ng, S Stefanoski, Peter Zavalij, George S. Nolas, Beekman Mathew

Abstract

During the studies of structure/property relationships of thermoelectric intermetallic clathrates, we found that while single crystals for representative clathrates are readily grown using established techniques or flux synthesis, crystal growth of many other compositions can be challenging. Historically synthesis in the binary Na-Si system has been complicated by the simultaneous formation of the two different structure types (clathrate-I and clathrate-II), which are characterized by nearly identical compositions. We demonstrated that selective, phase pure, single-crystal growth of both Na8Si46 and Na24Si136 can be achieved by simply maintaining sufficient Na partial pressures during slow, controlled deprivation of Na from the precursor Na4Si4. In this paper, we also describe the structure of these crystals which were studied using X-ray diffraction.

Citation

Angewandte Chemie-International Edition

Volume

23

Pub Type

Journals

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DOI Link

Keywords

Thermoelectric, Crystal growth, crystal structure, Type-I Na8Si46 clathrate, Type-II Na24Si136 clathrate

Citation

Wong-Ng, W. , Stefanoski, S. , Zavalij, P. , Nolas, G. and Mathew, B. (2011), A simple approach for selective crystal growth of Na8Si46 and Na24Si136, Angewandte Chemie-International Edition, [online], https://doi.org/10.1021/cm103135k (Accessed October 20, 2025)