DOI QR코드

DOI QR Code

Two Crystal Structures of $Tl^+$ and $Zn^{2+}$ Exchanged Zeolite A, $Tl_{12-2x}Zn_x-A$ (x=4.3 and 3.25)

  • Mi Suk Jeong (Department of Chemistry, Pusan National University) ;
  • Seong Hwan Song (Department of Chemistry, Pusan National University) ;
  • Young Wook Han (Department of Chemistry, Pusan National University) ;
  • Yang Kim (Department of Chemistry, Pusan National University)
  • Published : 1990.04.20

Abstract

The structures of $Tl_{12-2x}Zn_x-A$ (x = 4.3 and 3.25), vacuum dehydrated zeolite A with all $Na^+$ ions replaced by $Tl^+$ and $Zn^{2+}$ as indicated, have been determined by single-crystal X-ray diffraction techniques in cubic space group Pm3m at 21(1) $^{\circ}C$ (a=12.100(2) ${\AA}$ for $Tl_{3.4}Zn_{4.3}-A$ and a=12.092(2) ${\AA}$ for $Tl_{5.5}Zn_{3.25}-A$). The crystals of $Tl_{3.4}Zn_{4.3}-A$ and $Tl_{5.5}Zn_{3.25}-A$ were prepared by flow method using exchange solutions in which mole ratios of $TlNO_3$,/TEX> and $Zn(NO_3)_2$ were 1:50 and 1:1, respectively, with total concentration of 0.05 M. The structures of the dehydrated $Tl_{3.4}Zn_{4.3}-A$ and $Tl_{5.5}Zn_{3.25}-A$ were refined to yield the final error indices $R_1$ = 0.075 and $R_2$ = 0.075 with 236 reflections, and $R_1$ = 0.057 and $R_2$ = 0.064 with 202 reflections, respectively, for which I > 3$\sigma$(I). Both structures indicate that Zn(II) ions are coordinated by three framework oxygens: the Zn(II) to O(3) distances are 2.08(1) ${\AA}$ for $Tl_{3.4}Zn_{4.3}-A$ and 2.07(1) ${\AA}$ for $Tl_{5.5}Zn_{3.25}-A$, respectively. In each structure, the angle subtended at Zn(II), O(3)-Zn(II)-O(3) is 119.9(3)$^{\circ}$ for $Tl_{3.4}Zn_{4.3}-A$, and 120.0(3)$^{\circ}$ for $Tl_{5.5}Zn_{3.25}-A$, respectively, close to the idealized trigonal-planar value. Zn(II) ions prefer to 6-ring sites. $Tl^+$ ions do not have any preference to a particular site but occupy simultaneously both at the 6-ring sites and 8-ring sites.

Keywords

Cited by

  1. Framework-Type Determination for Zeolite Structures in the Inorganic Crystal Structure Database vol.39, pp.3, 1990, https://doi.org/10.1063/1.3432459
  2. Using Crystallography and NMR to Count the Number of Three-Aluminum Six-Rings in Fully Zn2+-Exchanged Zeolite Y. These Six-Rings Concentrate at Single Six-Ring Positions vol.125, pp.1, 2021, https://doi.org/10.1021/acs.jpcc.0c09682