Accessible Unlicensed Requires Authentication Published by Oldenbourg Wissenschaftsverlag February 18, 2013

Ab-initio structure determination of novel strontium-containing layered silicate AES-18 synthesized using mechanochemical reaction

Takuji Ikeda, Chiaki Ideta and Katsutoshi Yamamoto

Abstract

A new strontium-containing layered silicate, alkaline earth-containing silicate (AES)-18 [chemical composition: Si16O24(OH)16 · {Sr(OH)2}8 · (KOH)2], was synthesized utilizing a mechanochemical reaction in which an admixture of strontium hydroxide, which unfavorably precipitates in conventional syntheses, and a fumed silica (Aerosil) was allowed to react in the solid phase. The crystal structure of AES-18 was elucidated by the charge-flipping method using powder X-ray diffraction data, and the obtained structure was refined by a combination with the Rietveld method and the maximum entropy method (MEM). The structure analyses showed a tetragonal symmetry with a = 0.912738(3) nm, c = 1.628120(8) nm, and the space group P42/mnc. Two silicate layers composed of Q3 local structure [(—SiO)3Si—OH], 7-coordinated Sr2+ catäions, and K+ cations were included in a unit cell, and a Sr4(OH)17 cluster was formed between adjacent silicate layers. The framework topology of AES-18 containing 4- and 8-Si-membered rings was similar to that of paracelsian.


* Correspondence address: AIST Tohoku, Research Center for Compact Chemical System, Nigatake 4-2-1, Miyagino-ku, 983-8551 Sendai, Japan,

Published Online: 2013-02-18
Published in Print: 2013-04

© by Oldenbourg Wissenschaftsverlag, München, Germany