Synthesis and Crystal Structure of Zinc Iodide in the Sodalite Cavities of Zeolite A (LTA).

Abstract

Synthesis and Crystal Structure of Zinc Iodide in the Sodalite Cavities of Zeolite A (LTA). -K 6 Zn 3 (KI) 3 (ZnI 2 ) 0.5 [Si 12 Al 12 O 48 ]-LTA (LTA: zeolite A) is synthesized from a single crystal of Zn6[Si12Al12O48]-LTA (prepared by dynamic ion-exchange of Na12[Si12Al12O48]-LTA with aqueous Zn (NO3)2) placed in a stream of flowing KI in MeOH at 294 K for 4 d. Its structure is determined by single crystal XRD. The material crystallizes in the cubic space group Pm3m. Half a Zn 2+ ion and one Iion per unit cell exist in the sodalite cavities, indicating the formation of a ZnI 2 molecule in 50% of the sodalite cavities. The ZnI2 molecules in the sodalite cavities are probably highly resistant to heating and dehydration because they are stabilized by interactions with the framework atoms. Zeolites containing ZnI2 clusters in their unique-sized and regular three-dimensionally oriented cavities are predicted to be advanced catalytic and optical materials. -(KIM, S. H.; PARK*, M.; SON, Y. J.; LEE, H. J.; JEONG, G. C.; BAE, M. N.; LIM, W. T.; Bull. Korean Chem.

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

“…If more than eight cations are needed to balance the 12-negative charge per unit cell of the zeolite framework, the less suitable 8R sites are next occupied. 15 They found ZnI 2 clusters in the sodalite cavities and K 3 I 2+ and K 2 ZnI 3+ clusters in the large cavities. The Zn 2+ ions that did not participate in these clusters occupied two crystallographic sites, one of which was close to 6R planes.…”

“…Kim et al . treated hydrated |Zn 6 |[Si 12 Al 12 O 48 ]-LTA with 0.05 M KI in CH 3 OH . They found ZnI 2 clusters in the sodalite cavities and K 3 I 2+ and K 2 ZnI 3+ clusters in the large cavities.…”