Where are the Sn atoms in LaSb2Snx, 0.1⩽x⩽∼0.75?

✍ Scribed by Lasse Norén; Ray L. Withers; Frank J. Brink

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 961 KB
• Volume: 178
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2005.04.026

✦ Synopsis

The composition range and (composite modulated) structure of compounds within the wide range non-stoichiometric LaSb 2 Sn x , 0.1pxp0.75, solid solution is carefully investigated via a combined electron diffraction, XRD and electron probe microanalysis study. Evidence for metastability of the LaSb 2 Sn x phase at the low x composition end of the solid solution is presented. Direct evidence is found for a reasonably (although by no means perfectly) well ordered Sn sub-structure which is, in general, mutually incommensurable with respect to a very well ordered underlying LaSb 2 sub-structure along both a and c directions. The overall (3+2)-d superspace group symmetry is given along with a discussion of the consequences as regards the arrangement of the Sn atoms. The Sn sub-structure c-axis cell dimension shows very little variation with composition x providing direct experimental evidence of the importance of Sn-Sn metallic bonding (along one-dimensional [001] Sn strings) for the stability of the phase.