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-exchang e of the K+ ions for the smaller cations Li+ and NaC+ as well as for t he NH4+ at the remarkably low temperature regime of 110-130 degrees C. The topotactically ion-exchanged series A(x)K(1-x)Bi(3)S(5) (A = Li, Na, and NH4) was prepared and characterized by powder X-ray diffractio n, differential scanning calorimetry, differential thermal analysis, t hermal gravimetric analysis, semiquantitative microprobe analyses, sol id-state UV/vis/near-IR spectroscopy, and variable-temperature solid-s tate Li-7 NMR spectroscopy. (C) 1998 Academic Press.