Novel planar chain like Li7F7 and Li9F9 nanostructures

Li3F3 (trimer of LiF) appears structurally a close analog of the benzene ring. What about the naphthalene like Li5F5 and anthracene like Li7F7? Our density functional theory calculations do not allow realizing the structures of Li5F5 and Li7F7 analogous to naphthalene and anthracene. However, we find a stable planar chain like structure for Li7F7 and also for Li9F9, which possess mirror symmetries and enclosed with Li3F3 rings at their ends. We believe that it may be possible, at least theoretically, to continue this chain of (LiF)n clusters for n = (2m + 1; m ≥ 5).