Extraframework cation distributions in X and Y faujasite zeolites: A review

Cation redistribution upon dehydration of Na58Y faujasite zeolite: a joint neutron diffraction and molecular simulation study

“…Molecules Ow1 are positioned inside the sodalite cage and are coordinated to cations NaI', while Ow2 and Ow3 sit in the supercages, with Ow2 coordinating both NaII and NaIII, and Ow3 being only connected to NaIII. The observed inter atomic distances between oxygen atoms and cations lie between 2.42 and 2.83 Å in agreement with former crystallographic studies [1].…”

“…The standard definition of these sites follows from their coordinates in the crystal unit cell, which have to be determined experimentally. Figure 1 shows a schematic representation of the faujasite structure with the location of the four types of cationic sites widely documented in the literature [1]. For the specific case of Faujasite, sites I, I' and II lie along the The standard method for assigning a cation to a specific site is then based on its distance to all possible crystallographic sites in the unit cell.…”

“…The precise determination of cation location has thus been the subject of many works, both experimental and theoretical [1]. Extraframework cations are located in well-defined crystallographic sites [2] but their distribution among these sites is still a subject of fundamental studies.…”

“…Extraframework cations are located in well-defined crystallographic sites [2] but their distribution among these sites is still a subject of fundamental studies. One of the reasons for the discrepancy between cation location results is the strong sensitivity of cation distribution to experimental conditions (temperature, dehydration conditions, nature and quantity of sorbed molecules …) [1,3]. The presence of water has been shown to drastically modify the cation location in zeolites and in particular in faujasite zeolite [4,5,6,7,8].…”

Synthesis of Fully Dehydrated Partially Cs+-exchanged Zeolite Y (FAU, Si/Al = 1.56), |Cs45Na30|[Si117Al75O384]-FAU and Its Single-crystal Structure

“…[4][5][6] In addition, Cs + -exchanged faujasite-type zeolites are used in fuel/gasoline desulphurization processes. 7 The crystal structures of Cs + -exchanged faujasite-type zeolites have been reported by several scientists. [8][9][10][11][12] Smolin et al investigated hydrated and dehydrated partially Cs + -exchanged zeolite X (Si/Al = 1.11 (2)) with an exchanged level of 0.48 (4) by using the single-crystal X-ray diffraction technique.…”