“…[6,7,9] Li 3 [PS 4 ] [10,11,12] and Na 3 [PS 4 ] [13] or even the europium(II)-containing LiEu[PS 4 ] [14] are also examples of thiophosphate-based alkali-metal cation conductors. Moreover, the lithium-containing rare-earth metal(III) ortho-thiophosphates(V) with the compositions Li 3 RE[PS 4 ] 2 (RE = La), [15] Li 9 RE 2 [PS 4 ] 5 (RE = Pr, Nd, [16] Sm, Gd, Er, Yb [17] ) [18] and Li 6 RE 3 [PS 4 ] 5 (RE = Y, Gd, Dy, Yb, [17] Lu) [19] can be treated as mixtures of Li 3 [PS 4 ] and RE[PS 4 ] [20] according to (Li 3 [PS 4 ]) x (RE[PS 4 ]) y with a ratio of integer numerators and denominators for the fraction x/y. [4] In the composition Li 3 RE[PS 4 ] 2 , so far only scarcely known, e. g. for RE = La, [15] but also predicted for RE = Y, [21] the x/y-ratio of Li 3 [PS 4 ] to RE[PS 4 ] equals 1.0, whereas for the Li 9 RE 2 [PS 4 ] 5 representatives the x/y-ratio becomes 1.5.…”