New Topotactic Derivatives of the Open-Framework Semiconductor KBi3S5via a Low-Temperature Solid-State Ion-Exchange Route

A new low-temperature solid-state ion-exchange route has been used to ion-exchange KBi3S5. The new method allows the solid–solid ion-exchange of the K+ions for the smaller cations Li+and Na+, as well as for the NH+4at the remarkably low temperature regime of 110–130°C. The topotactically ion-exchanged seriesAxK1−xBi3S5(A=Li, Na, and NH4) was prepared and characterized by powder X-ray diffraction, differential scanning calorimetry, differential thermal analysis, thermal gravimetric analysis, semiquantitative microprobe analyses, solid-state UV/vis/near-IR spectroscopy, and variable-temperature solid-state7Li NMR spectroscopy.