Metal Sulfide Ion Exchangers: High Acid Stability of NaMgSnS (NMS) and Topotactic Conversion to 2D Solid Acids with Semiconducting Character.

Metal sulfide ion exchange materials (MSIEs) are of interest for nuclear waste remediation applications. We report the high stability of two structurally related metal sulfide ion exchange materials, NaMgSnS (Mg-NMS) and NaSnS (Na-NMS), in strongly acid media, in addition to the preparation of NaNiSnS (Ni-NMS). Their formation progress during synthesis is studied with in-situ methods, with the target phases appearing in <15 min, reaction completion in <12 h, and high yields (75-80%).