Si-29 and O-17 NMR investigation of the structure of some crystalline calcium silicate hydrates
Si-29 and O-17 NMR investigation of the structure of some crystalline calcium silicate hydrates
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DOI：
10.1016/s1065-7355(96)90045-0
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发表时间：
1996-04-01
期刊：
影响因子：
--
通讯作者：
Kirkpatrick, RJ
中科院分区：
文献类型：
--
作者：
Cong, XD;Kirkpatrick, RJ
本文用Si-29魔角旋转(MAS)、H-1-Si-29交叉极化魔角旋转(CPMAS)和O-17魔角旋转(CPMAS)核磁共振对水热合成的1.1 nm托贝莫来石、1.4 nm托贝莫来石、珍珠石、硬硅钙石和硬硅钙石的结构进行了系统的研究。O-17和大多数H-1-Si-29的CPMAS结果是这些相的首次报道。在托勃莫来石和珍珠岩中观察到六种类型的氧位，包括Si-OH和Ca-OH键。1.4nm托贝莫来石的结构类似于1.1nm托贝莫来石，其中约26%的Ca~(2+)~(2+)存在于层间S。这一结果支持所提出的沿CaO层交替出现硅酸链和一排排OH-基团的珍珠岩结构。珍珠岩含有与1.4 nm托贝莫来石相似的长的单硅酸链，Si-OH位主要出现在桥联四面体上，似乎没有层间Ca~(2+)~(2+)S。尽管硬硅钙石和软骨石中的Si位交叉极化良好，但都不存在Si-OH键。
This paper presents the results of a systematic investigation of the structure of O-17-enriched, hydrothermally synthesized 1.1-nm tobermorite, 1.4-nm tobermorite, jennite calciochondrodite, xonotlite, and hillebrandite, using Si-29 magic angle spinning (MAS) NMR, H-1-Si-29 cross-polarization magic angle spinning (CPMAS) NMR, and O-17 MAS NMR. The O-17 and most of the H-1-Si-29 CPMAS results are the first reported for these phases. Six types of oxygen sites were observed in tobermorite and jennite, including both Si-OH and Ca-OH linkages. The structure of 1.4-nm tobermorite is similar to that of 1.1-nm tobermorite with about 26% of the Ca2+'s in the interlayers. The results support the proposed jennite structure in which silicate chains and rows of OH- groups alternately occur along the CaO layers [1]. Jennite contains long, single silicate chains similar to those in 1.4-nm tobermorite, with Si-OH sites primarily occurring on bridging tetrahedra, and there seems to be no interlayer Ca2+'s. Although the Si sites in xonotlite and calciochondrodite cross-polarize well, neither contains Si-OH linkages.