Synthesis and Crystal Structure of a New Salt of the Water‐Stable Hexathiohypodiphosphate Anion: [py₂Li]₄[P₂S₆] ·2 py

Abstract

A new rare example of a synthetic route in solution to the hexathiohypodiphosphate anion P2S64− is presented. Starting from P4S3, Li2S, and elemental sulfur in pyridine, this reaction yields yellow block‐shaped crystals of [py2Li]4[P2S6] · 2 py (1). The molecular structure of this hitherto unknown compound was determined by single crystal X‐ray diffraction and reveals a heteronorbornane skeleton within the Li4P2S6 entity.

Pyridine Complexes as Tailored Precursors for Rapid Synthesis of Thiophosphate Superionic Conductors

“…There are also two fairly strong peaks at 1003 cm −1 and 1034 cm −1 ; this is not representative of free pyridine (ν 1 and ν 12 at 991 cm −1 and 1030 cm −1 ) but rather pyridine complexed to Li + cations, for instance in zeolites (1002 cm −1 and 1036 cm −1 ) [25] . This result suggests that, despite being immersed in excess ACN, pyridine molecules originally bound to the phosphorus atoms of P 2 S 5 remain preferentially complexed to the material even after reaction (though likely now complexed to Li + , as demonstrated by Schönberger and coworkers with py 8 Li 4 P 2 S 6 ) [26] . There is a small peak at 385 cm −1 ; this possibly belongs to the undesirable P 2 S 6 4− anion (to preserve stoichiometry, its formation would require a temporary sink for excess S; PS 4 3− units themselves have been suggested as a possibility for this) [27,28] .…”

Anomalous superionic conductivity in van der Waals lithium thiophosphates triggered by interlayer molecules

“…Notably, the [P 2 S 6 ] 4À polyanion is remarkably stable in water, and several LTPs are stable in air for extended periods of time. 14 Therefore, we first examine the air stability of the LiInP 2 S 6 material. Upon exposure of the pristine LiInP 2 S 6 powder to humid air, the change of color rapidly takes place from pale yellow to deep yellow (Fig.…”

“…[11][12][13] exhibit much better chemical stability and are remarkably stable to water molecules, thus it is of great interest to develop the new generation of sulfide SICs based on [P 2 S 6 ] 4À frameworks. 14 In solid-state materials, the ion transport depends on the ion hopping and migration from the lattice to a vacancy, or from one interstitial to adjacent interstitial along the favorable pathways. 15 Thus, a SIC requires a low migration energy barrier and fast inter-connected Li ion diffusion pathways.…”

“…11–13 [P 2 S 6 ] 4− frameworks exhibit much better chemical stability and are remarkably stable to water molecules, thus it is of great interest to develop the new generation of sulfide SICs based on [P 2 S 6 ] 4− frameworks. 14…”