Disordering in the structure of cesium silicate Cs6Si10O23

Abstract

This paper reports on the results of an X-ray diffraction study of the crystal structure of cesium silicate Cs 6 Si 10 O 23 prepared by crystallization from a glass of mixed composition.

Structural analysis of alkali cations in mixed alkali silicate glasses by 23Na and 133Cs MAS NMR

“…The melt was slowly cooled at a rate of 0.1 • C/min. Similarly, the Cs 6 Si 10 O 23 crystals were prepared using a glass heating process [19]. Starting materials in amounts corresponding to Cs 2 O-4SiO 2 were mixed and melted in a platinum crucible at 1350 • C for 1 h, then quenched by immersing the bottom of the platinum crucible in water.…”

“…As Cs 2 Si 2 O 5 crystals are highly susceptible to the moisture absorbed from air, they were enclosed in a capillary tube made of borosilicate glass and fixed onto a jig during the measurements. In addition, the XRD patterns were also simulated from the crystal structure data [18,19] by using POWDER CELL [20].…”

“…Similarly, the XRD pattern of the Cs 6 Si 10 O 23 crystal also shows a trace of an amorphous peak at around 26 • , corresponding to the glass remaining after the production process. All other diffraction peaks could be indexed to the crystal structure of Cs 6 Si 10 O 23 [19], whose peaks were simulated by using POWDER CELL like those of Cs 2 Si 2 O 5 . The XRD patterns of both cesium silicate crystals revealed a single phase without any impurities or mixed phases.…”

The New Alkali Cyclotrisilicate Cs8[Si6O16]

“…The smallest unbranched ring consisting of three condensed [SiO 4 ] tetrahedra is found in the mineral benitoite, BaTi[Si 3 O 9 ]. [16] The existence of unbranched dimeric cyclotrisilicate anions has been predicted by Liebau, [2] and the general formula has been given as {uB, 2r} [12] or under hard HT-HP natural conditions as in case of the mineral moskvinite-(Y) Na 2 KY[Si 6 O 15 ], found in Tian-Shan moutains and having most probably a volcanic origin.…”

“…[3] An overview, including a classification and predictions of silicates was presented by Liebau. [2] So far, several structurally characterized caesium silicates have been reported: Cs 6 Si 10 O 23 with a 3D silicate anion, [4] Cs 2 Si 2 O 5 with a 2D structure, [5] and Cs 6 Si 3 O 9 and Cs 6 Si 2 O 7 with isolated (0D) cyclotrisilicate and sorosilicate anions. [6] In the crystal structure of the recently described silicide-silicate Cs 10 [7] the Zintl anion [Si 4 ] 4-coexists with the cyclotrisilicate ion [Si 3 O 9 ] 6-with the latter known from the silicate Cs 6 Si 3 O 9 .…”