X-ray and neutron diffraction studies on Li4.4Sn

A chemical analysis and detailed structural characterization, using X-ray single crystal and neutron powder diffraction, of the binary lithium-tin compound Li4.4Sn is presented. Phase analyses and subsequent structural refinements result in the reformulation of Li4.4Sn as Li17Sn4. The lithium-rich binary phase crystallizes with a complex cubic structure in the space group F43m, with a = 19.6907(11) Angstrom, Z = 20. The improved crystal structure determination indicates well-defined lithium atom positions, some of which differ from those previously reported. The nearly Zintl phase Li17Sn4 exhibits poor metallic behavior similar to that of heavily doped semiconductors. Comparisons of the refined crystal structure with previously reported X-ray crystal structures associated with Li4.4Sn are discussed.