Crystal structure of K_{1- x} Cs _x BSi₂O₆ (x = 0.12, 0.50) boroleucite solid solutions and thermal behaviour of KBSi₂O₆ and K_0.5Cs_0.5BSi₂O₆

Abstract

The crystal structures of two K 1Àx Cs x BSi 2 O 6 solid solutions have been refined at room temperature by the Rietveld method:They are isostructural to cubic KBSi 2 O 6 with the space group I 4 43d. The structure is built up from (Si,B)O 4 tetrahedra linked in four-, six-and eightfold rings which are forming a three-dimensional borosilicate framework. The framework contains large cavities that are placed in continuous channels along the [111] directions. The Cs and K atoms occupy the positions in the channels statistically.Thermal behaviour of KBSi 2 O 6 and K 0.5 Cs 0.5 BSi 2 O 6 has been studied by high-temperature powder X-ray diffraction within the temperature range of 293-1073 K. A new tetragonal polymorph of KBSi 2 O 6 has been found in situ under heating. The new polymorphic I 4 43d (cubic) -Ia 3 3d (cubic) transition and the new Ia 3 3d cubic polymorphic phase has been proposed for K 1Àx Cs x BSi 2 O 6 from our experimental and literature data on crystal structures and thermal expansion of leucites. The structural relaxation under cationic (K, Cs) substitutions and under heating has been investigated.

Crystal structure and thermal behaviour of (Rb,Cs)BSi2O6 solid solutions

“…The same character of leucite structure transformations under K-Cs substitution was reported recently in [4] for K 1-x Cs x BSi 2 O 6 solid solutions.…”

Template burning effects on stability and boron coordination in boron levyne studied by in situ time resolved synchrotron powder diffraction

“…In spite of the large number of both experimental and computational studies, very few detailed structural investigations have been conducted so far to explore changes in the structures of borosilicate zeolites [44][45][46][47][48][49][50][51][52]. In particular, these studies are exclusively dedicated to boron leucite type materials and only in one case (Martucci et al [52]) the evolution of the structural features as a function of temperature was followed by full profile Rietveld analysis.…”

Effects of cation field strength on the structure of aluminoborosilicate glasses: High-resolution 11B, 27Al and 23Na MAS NMR

“…Many studies have documented the close relationships between physical properties and structure of boron-containing glasses [11][12][13][14][15][16][17][18]. Extensive efforts have also been made to model the effects of composition on properties [19][20][21], many of which are based on structural speciation reactions [22][23][24][25][26][27].…”