Bulletin of the Korean Chemical Society

Korean Chemical Society (대한화학회)
권호 표지
DOI QR코드

DOI QR Code

Two Anhydrous Zeolite X Crystal Structures, $Ca_{31}Rb_{30}Si_{100}Al_{92}O_{384}$ and $Ca_{28}Rb_{36}Si_{100}Al_{92}O_{384}$

  • Published : 1996.07.20
Download PDF
⟨ Previous Next ⟩

Abstract

The structures of fully dehydrated Ca2+- and Rb+-exchanged zeolite X, Ca31Rb30Si100Al92O384(Ca31Rb30-X; a=25.009(1) Å) and Ca28Rb36Si100Al92O384(Ca28Rb36-X; a=24.977(1) Å), have been determined by single-crystal X-ray diffraction methods in the cubic space group Fd&bar{3} at 21(1) ℃. Their structures were refined to the final error indices R1=0.048 and R2=0.041 with 236 reflections for Ca31Rb30-X, and R1=0.052 and R2=0.043 with 313 reflections for Ca28Rb36-X; I>3σ(I). In both structures, Ca2+ and Rb+ ions are located at six different crystallographic sites. In dehydrated Ca31Rb30-X, sixteen Ca2+ ions fill site I, at the centers of the double 6-rings (Ca-O=2.43(1) Å and O-Ca-O=93.3(3)°). Another fifteen Ca2+ ions occupy site II (Ca-O=2.29(1) Å, O-Ca-O=119.5(5)°) and fifteen Rb+ ions occupy site II opposite single six-rings in the supercage; each is 1.60 Å from the plane of three oxygens (Rb-O=2.77(1) Å and O-Rb-O=91.1(4)°). About two Rb+ ions are found at site II', 1.99 Å into sodalite cavity from their three-oxygen plane (Rb-O=2.99(1) Å and O-Rb-O=82.8(4)°). The remaining thirteen Rb+ ions are statistically distributed over site III, a 48-fold equipoint in the supercages on twofold axes (Rb-O=3.05(1) Å and Rb-O=3.38(1) Å). In dehydrated Ca28Rb36-X, sixteen Ca2+ ions fill site I (Ca-O=2.41(1) Å and O-Ca-O=93.6(3)°) and twelve Ca2+ ions occupy site II (Ca-O=2.31(1) Å, O-Ca-O=119.7(4)°). Sixteen Rb+ ions occupy site II; each is 1.60 Å from the plane of three oxygens (Rb-O=2.81(1) Å and O-Rb-O=90.6(3)°) and four Rb+ ions occupy site II'; each is 1.88 Å into sodalite cavity from their three-oxygen plane (Rb-O=2.99(1) Å and O-Rb-O=83.8(2)°). The remaining sixteen Rb+ ions are found at III site in the supercage (Rb-O=2.97(1) Å and Rb-O=3.39(1) Å). It appears that Ca2+ ions prefer sites I and II in that order, and that Rb+ ions occupy the remaining sites. Rb+ ions are too large to be stable at site I, when they are competing with other smaller cations like Ca2+ ions.

Keywords

References

  1. Compilation of Extra-framework Sites in Zeolites Mortier, W. J.
  2. Phys. Chem.(Leipzig) v.262 Schollner, R.;Broddack, R.;Kuhlmann, B.;Nozel, P.;Herden, H. Z.
  3. J .Chem. Soc., Faraday Trans. Ⅰ v.66 Egerton, T. S.;Stone, F. S.
  4. Zeolites v.6 Calligaris, M.;Mezzetti, A.;Nardin, G.;Randaccio, L.
  5. Zeolites v.5 Calligaris, M.;Mezzetti, A.;Nardin, G.;Randaccio, L.
  6. Mater. Res. Bull. v.12 Pluth, J. J.;Smith, J. V.;Mortier, W. J.
  7. J. Chem. Soc., Dalton Trans. Bresciani-Pahor, N.;Calligaris, M.;Narin, G.;Randaccio, L.;Russo, E.;Comin-Chiaramonti, P.
  8. Acta Crystallogr. v.45 Smolin, Y. I.;Shepelev, Y. F.;Anderson, A. A.
  9. Zeolite v.11 Shepelev, Y. F.;Butikova, I. K.;Smolin, Yu. I. K.;Smolin, Yu. I.
  10. J. Korean Chem. Soc. v.39 Jang, S. B.;Song, S. H.;Kim, Y.
  11. Zeolites v.6 Bogomolov, V. N.;Petranovskii, V. P.
  12. J. Phys. Chem. v.97 Kim, Y.;Han, Y. W.;Seff, K.
  13. Handbook of Chemistry and Physics(70th ed.) The Chemical Rubber Co.
  14. International Tables for X-ray Crystallography v.Ⅱ Kynoch Press
  15. Acta Crystallogr. v.18 Cromer, D. T.
  16. International Tables fot X-ray Crystallograpy v.Ⅳ Kynoch Press
  17. International Tables fot X-ray Crystallograpy v.Ⅳ Kynoch Press
  18. J. Phys. Chem. Kwon, J. H.;Jang, S. B.;Kim, Y.;Seff, K.
  19. Bull. Korean Chem. Soc. v.16 Jang, S. B.;Kim, Y.
  20. J. Korean Chem. Soc. v.39 Jang, S. B.;Song, S. H.;Kim, Y.
  21. J. Phys. Chem. Yeom, Y. H.;Jang, S. B.;Song, S. H.;Kim, Y.;Seff K.
  22. J. Phys. Chem. v.72 Sherry, H. S.