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The structure of calcium metaphosphate glass obtained from x-ray and neutron diffraction and reverse Monte Carlo modelling

Wetherall, Karen, Pickup, David M., Newport, Robert J., Mountjoy, Gavin (2009) The structure of calcium metaphosphate glass obtained from x-ray and neutron diffraction and reverse Monte Carlo modelling. Journal of Physics: Condensed Matter, 21 (3). ISSN 0953-8984. (doi:10.1088/0953-8984/21/3/035109) (KAR id:19151)

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http://dx.doi.org/10.1088/0953-8984/21/3/035109

Abstract

The short range structure of (CaO)(0.5)(P2O5)(0.5) glass has been studied using x-ray and neutron diffraction and modelled using the reverse Monte Carlo method. Using this combination of techniques has allowed six interatomic correlations to be distinguished and fitted to obtain a set of bond lengths and coordination numbers that describe the structure of the glass. The glass consists of metaphosphate chains of phosphate tetrahedra and each phosphate unit has two non-bridging oxygen atoms available for coordination with Ca. The Ca-O correlation was fitted with two peaks at 2.35 and 2.86 angstrom, representing a broad distribution of bond lengths. The total Ca-O coordination is 6.9 and is consistent with distorted polyhedral units such as capped octahedra or capped trigonal prisms. It is found that most non-bridging oxygen atoms are bonded to two calcium atoms. All of these observations are consistent with Hoppe's model for phosphate glasses. Furthermore, the medium range order is revealed to consist of phosphate chains intertwined with apparently elongated clusters of Ca ions, and the Ca-O and Ca-P correlations contributed significantly to the first sharp diffraction peak in x-ray diffraction.

Item Type: Article
DOI/Identification number: 10.1088/0953-8984/21/3/035109
Additional information: Grant Number EPSRC EP/E006337/1
Subjects: Q Science
Divisions: Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: J.M. Smith
Date Deposited: 18 May 2009 13:27 UTC
Last Modified: 27 Jan 2020 04:02 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/19151 (The current URI for this page, for reference purposes)
Newport, Robert J.: https://orcid.org/0000-0002-2365-992X
Mountjoy, Gavin: https://orcid.org/0000-0002-6495-2006
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