Abstract
Two crystal structures of dehydrated $Ag^+-andTl^+$-exchanged zeolite X$Ag_{27}Tl_{65-}X\;and\;Ag_{23}Tl_{69-}X$have been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 at 21(1) $^{\circ}C(a=24.758(4)\AAa=24.947(4)$, ${\AA}respectively).$, Their structures were refined to the final error indices $R_1$=0.055 and $wR_2$=0.057 with 375 reflections, and $R_1$=0.057 and $wR_2$=0.057 with 235 reflections, respectively, for which I > $3\sigma(I).$ In the structure of $Ag_{27}Tl_{65-}X,\;27\;Ag^+$ ions were found at two crystallographic sites: 15$Ag^+$ ions at site I at the center of the hexagonal prism and the remaining 12$Ag^+$ ions at site II' in the sodalite cavity. Sixty-five $Tl^+$ ions were located at three crystallographic sites: 20$Tl^+$ ions at site II opposite single six-rings in the supercage, 18$Tl^+$ ions at site I' in the sodalite cavity opposite the D6Rs, and the remaining 27$Tl^+$ ions at site III' in the supercage. In the structure of $Ag_{23}Tl_{69-}X$, 23$Ag^+$ ions were found at two crystallographic sites: 15 at site I and 8 at site II'. Sixty-nine $Tl^+$ ions are found at four crystallographic sites: 24 at site II, 17 at stie I', and the remaining 28 at two III' sites with occupancies of 22 and 6.