Rational Syntheses and Structural Characterization of Sulfur‐Rich Phosphorus Polysulfides: α‐P₂S₇ and β‐P₂S₇

Abstract

A wide range of binary compounds is known in the system phosphorus-sulfur. They consist of discrete cage-like molecules with the composition P 4 S n (n = 3-10) except for P 14 S. [1] The cages can formally be derived from the P 4 tetrahedron of white phosphorus either by insertion of sulfur atoms into P À P bonds or by exocyclic addition to phosphorus atoms. The maximum amount of sulfur per molecule is present in P 4 S 10 . [2] The congruently melting phosphorus sulfides P 4 S 3 , P 4 S 7 , and P 4 S 10 are synthesized by reaction of stoichiometric amounts of the elements in the melt. [3] Other phosphorus sulfides are not accessible by this route. For instance, a-P 4 S 5 is prepared by stirring a solution of P 4 S 3 , sulfur, and catalytic amounts of iodine in dry carbon disulfide at room temperature and diffuse daylight for three days. [4] Jason used triphenylarsenic sulfide and triphenylantimony sulfide as sulfur transfer reagents in the synthesis of g-P 4 S 6 , for example. [5] Another very useful sulfur transfer reagent is [(CH 3 ) 3 Sn] 2 S. [6] In contrast triphenylphosphine is suitable for the abstraction of sulfur atoms. [7] Note that the syntheses of phosphorus sulfides often result in mixtures of different compounds. In addition, various modifications of phosphorus sulfides of the same composition are known. Unfortunately the nomenclature is far from systematic. In fact, it is a quite confusing mix of Greek letter prefixes and Roman numeral suffixes that are used to distinguish between both different constitution isomers and different crystal structures of identical cage molecules. Herein we use Greek letter prefixes, not only to distinguish between two polymorphs but also to consider the chronological order of their discovery.As already mentioned P 4 S 10 is the most sulfur-rich phosphorus sulfide structurally characterized to date. However there is evidence for the existence of more sulfur-rich compounds P 4 S n with n > 10. [8] As early as 1910 Stock suspected that P 4 S 10 was not the most sulfur-rich phosphorus sulfide at all. [9] DØmarcq prepared PS x (x = 3-75) by heating P 4 S 10 with an excess of sulfur at 300 8C. [10] The corresponding solution 31 P NMR spectra indicated a number of novel species. He termed these compounds as "phosphorus polysulfides" or "phosphorus persulfides" implying the presence of S À S bonds. Though the system phosphorus-sulfur has been investigated for a long time, there are no structural data of phosphorus poly-(or per-) sulfides available.More than 150 years after the discovery of P 4 S 10 by Berzelius in 1843, we herein present the first crystal structure determinations of phosphorus polysulfides, namely a-P 2 S 7 and b-P 2 S 7 .The structures of a-P 2 S 7 and b-P 2 S 7 differ dramatically from those of common phosphorus sulfides. They do not consist of discrete cage-like molecules but of neutral polymeric strands featuring direct SÀS bonds. Both the polymers catena-P 2 S 7 in a-P 2 S 7 and in b-P 2 S 7 are quite similar: each phosphorus atom is tetrahedrally surr...

Toward Higher Voltage Solid‐State Batteries by Metastability and Kinetic Stability Design

“…For K eff = 0 GPa, our simulation in Figure 2b suggests that sulfur in LGPS is the most likely to be oxidized, forming S 0  (P 2 S 7 ) and S 0 (elemental sulfur) above 2.41 V. Note that there are two types of S bonds in polysulfides, the bridging sulfur in PS 0 P with a XPS peak at 163.5 eV and the non‐bridging sulfur in PS at 162.1 eV. [ 25–28 ] XPS peak of bridging S 0  (163.5 eV) or S 0 (163.9 eV) [ 29 ] should show very similar charge state, and obviously higher than S 2− (161.4 eV) [ 29–31 ] in LGPS. Therefore, the large purple peak at 163.4 eV in Figure 2c2 is likely from the oxidized sulfur in S or P 2 S 7 due to the lack of mechanical constriction in the liquid battery cell.…”

The Crystal and Molecular Structure of γ‐P4S6

“…They show a ratio of P:S Ͻ 4:10 and are the first well-characterized crystalline polymeric phosphorus polysulfides. [21] Experimental Section P 4 S 3 was prepared by reaction of stoichiometric amounts of the elements, phosphorus (Hoechst, 99.999 %) and sulfur (Chempur, 99.999 %) in an evacuated silica ampoule at 300°C and purified by recrystallization from toluene (Merck, p.A.). Commercial FeCl 3 (Fluka, Ͼ98 %) was purified by sublimation in a stream of chlorine gas at 250°C.…”

Oxygen, sulfur, selenium, tellurium and polonium

“…The reaction of P 4 S 3 with sulfur in the presence of a small amount of FeCl 3 yields crystalline a-P 2 S 7 and b-P 2 S 7 . 82 The transesterification of methyl aryl phosphorothioates is catalysed by Cd(II), Mn(II), and Pd(II). 83 Addition of sulfur to a phosphaalkene double bond led to the formation of the 1,2l 3 ,s 3 -thiaphosphirane 16.…”