Ordering of calcium and vacancies in calcium catapleiite CaZr[Si3O9] • 2H2O


Citar

Texto integral

Acesso aberto Acesso aberto
Acesso é fechado Acesso está concedido
Acesso é fechado Somente assinantes

Resumo

A sample of holotypic calcium catapleiite from the Burpala alkaline massif (Northern Baikal, Russia) is studied by single crystal X-ray analysis at 120 K and IR spectroscopy. The empirical formula of calcium catapleiite is Ca0.97Na0.02Zr1.01Si3O9 • 2H2O (Z = 4). The X-ray diffraction study confirms the orthorhombic unit cell with the following parameters: a = 7.406(1), b = 12.687(1), and c = 10.112(1) Å; V = 950.1(2) Å3; space group Pbnn. The crystal structure is refined in the anisotropic approximation of atomic displacement parameters using 1177 reflections with I > 2σ(I) to the final R = 2.91%. The structure of calcium catapleiite under study is based on the microporous heteropolyhedral framework formed by ZrO6 octahedra and threemembered silicon–oxygen rings [Si3O9]. It is on the whole analogous to the structures of the samples studied earlier, but differs from them by a high degree of ordering of calcium and vacancies at extraframework positions. The distribution of calcium over Ca1 and Ca2 positions in the calcium catapleiite structure leads to the formation of zigzag chains of the …Сa1–Zr–Ca1–Zr… and …Сa2–h–Ca2–□… types. Low occupancy of the Ca2 position and its alternation with the vacancy are prerequisites for potential Ca2+ cationic conduction.

Sobre autores

S. Aksenov

Shubnikov Institute of Crystallography; Vernadsky Institute of Geochemistry and Analytical Chemistry

Autor responsável pela correspondência
Email: aks.crys@gmail.com
Rússia, Leninskii pr. 59, Moscow, 119333; ul. Kosygina 19, Moscow, 119991

A. Portnov

Russian State Geological Prospecting University

Email: aks.crys@gmail.com
Rússia, ul. Miklukho-Maklaya 23, Moscow, 117997

N. Chukanov

Institute of Problems of Chemical Physics

Email: aks.crys@gmail.com
Rússia, pr. Akademika Semenova 1, Noginskii raion, Chernogolovka, Moscow oblast, 142432

R. Rastsvetaeva

Shubnikov Institute of Crystallography

Email: aks.crys@gmail.com
Rússia, Leninskii pr. 59, Moscow, 119333

Yu. Nelyubina

Nesmeyanov Institute of Organoelement Compounds

Email: aks.crys@gmail.com
Rússia, ul. Vavilova 28, Moscow, 119334

N. Kononkova

Vernadsky Institute of Geochemistry and Analytical Chemistry

Email: aks.crys@gmail.com
Rússia, ul. Kosygina 19, Moscow, 119991

M. Akimenko

Vernadsky Institute of Geochemistry and Analytical Chemistry

Email: aks.crys@gmail.com
Rússia, ul. Kosygina 19, Moscow, 119991

Arquivos suplementares

Arquivos suplementares
Ação
1. JATS XML

Declaração de direitos autorais © Pleiades Publishing, Inc., 2016