A review of the structural diversity of [P _x S _y ] ^{n −} motifs and their potential application prospects in metal thiophosphates

Abstract

Metal thiophosphates have wide potential critical applications in various fields, such as nonlinear optical materials, magnetic materials, photoluminescence materials and solid electrolytes. However, a detailed review of the relationship among structure, performance and application in thiophosphates has not been reported so far. In this work, we have undertaken integrated generalization for the structural features and application prospects of 312 known metal thiophosphates (117 ternary and 195 quaternary). A survey of their crystal structures shows that they have various link modes used to form the [P x S y ] n − ligands through the [PS4]3− building unit, for example, the ethane-like [P2S6]4− dimer, edge-sharing [P2S6]2−, corner-sharing [P2S7]4−, cyclic [P3S9]3− cluster, corner-sharing [P3S10]5− cluster, corner-sharing [P4S13]6− cluster and corner-sharing [P4S12]4− ring. Interestingly, various (P-S) ligands can also link other motifs to compose different structural features including zero-dimensional (0D) clusters, 1D chains, 2D layers and 3D networks. A detailed survey provides clear recognition of the inherent structure–performance relationship for thiophosphates and this result also illustrates that thiophosphates have huge potential as superior multifunctional materials.

Superionic Conduction in the Plastic Crystal Polymorph of Na4P2S6

“…The ability of sulfur to form disulfur -S–S- bridges and the broad range of oxidation states of phosphorus allow for even larger, ring-like or square-shaped anions. 1 , 2 …”

Eu2P2S6: The First Rare‐Earth Chalcogenophosphate Exhibiting Large Second‐Harmonic Generation Response and High Laser‐Induced Damage Threshold

“…In addition to choosing appropriate cations, reliable NLO material design from known structures is also important. Compared with traditional chalcogenides, chalcogenophosphates have been relatively rarely explored as MIR NLO materials in view of the far fewer noncentrosymmetric (NCS) members and the synthetic difficulties [36] . Since phosporus has variable oxidation states (usually +2 to +5) and is prone to form highly polar P−P bonds, the common anionic units in this system include [PQ 4 ] 3− , [P 2 Q 6 ] 4− , [P 2 Q 9 ] 4− and [P 2 Q 10 ] 4− [37] .…”

“…Compared with traditional chalcogenides, chalcogenophosphates have been relatively rarely explored as MIR NLO materials in view of the far fewer noncentrosymmetric (NCS) members and the synthetic difficulties. [36] Since phosporus has variable oxidation states (usually + 2 to + 5) and is prone to form highly polar PÀ P bonds, the common anionic units in this system include [PQ 4 ] 3À , [P 2 Q 6 ] 4À , [P 2 Q 9 ] 4À and [P 2 Q 10 ] 4À . [37] These fundamental building blocks (FBBs) can effectively interact with other NLO functional motifs to form a variety of polarizable structures, which provides a good platform for exploring high-performance NLO materials.…”

Accessing polyanionic redox in high voltage Li-rich thiophosphates

“…Polyanionic thiophosphates can be formed with a wide range of [P x S y ] nstoichiometries (x = 1-4, y = 4-12, and n = 2-6), such as [PS 4 ] 3and [P 2 S 6 ] 2-. 31 These polyanions exhibit P-P and P-S covalent bonding, which is expected to influence both cationic and anionic redox behaviour. Amongst the few previous studies on thiophosphate cathodes, 32,33 Li 2 FeP 2 S 6 has the highest reported voltage for a sulfide of 3 V, which is significantly higher than the voltage of ⇠2.3 V reported for the corresponding sulfide Li 2 FeS 2 .…”