Lithium transition metal pnictides – structural chemistry, electrochemistry, and function

Abstract

Lithium-transition metal (T)-pnictides (Pn = P, As, Sb, Bi) are an interesting class of materials with greatly differing crystal structures. The transition metal and pnictide atoms build up covalently bonded networks that leave cavities or channels for the lithium atoms. Depending on the bonding of lithium to the polyanionic network, one observes mobility of the lithium atoms. The crystal chemistry, chemical bonding, 7 Li solid-state NMR, and the electrochemical behavior of the pnictides are reviewed. The structural chemistry is compared with related tetrelides.

Na7TaP4: A Ternary Sodium Phosphidotantalate Containing [TaP4]7– Tetrahedra

“…Lithium phosphidotantalates are even more unexplored. Only one phase is mentioned in the literature: Li 7.5 Ta 0.5 P 4 crystallizes in an anti-CaF 2 -typ with statistically distributed TaP 4 tetrahedra. , Despite the above-mentioned compounds, there are no further phases with TaP 4 tetrahedra, but two niobium compounds are mentioned in the literature featuring NbP 4 tetrahedra: Li 7 NbP 4 , , which crystallizes in an anti-CaF 2 structure, and Na 5 SrNbP 4 , which is isotypic to Na 5 SrTaP 4 .…”

Zr4CuSb7 – A PbFCl-related Polyantimonide, and Structure Relations of Zirconium-Transition Metal Polyantimonides

“…The separating unit in Zr 2 T Sb 3 is a planar, non-corrugated 4 4 net formed by T and Sb atoms while in Zr 3 T Sb 7 the same 4 4 net is only generated by Sb atoms. Recently, review articles on structure-chemical properties and the electrochemical performance of antimonides and polyan-timonides have been published summarizing the intriguing structural chemistry and the performance of antimony-containing compounds as anodes for batteries [8,9].…”