Neutron and X-ray diffraction and empirical potential structure refinement modelling of magnesium stabilised amorphous calcium carbonate

G. Cobourne; G. Mountjoy; Juan Diego Rodriguez Blanco; L.G. Benning; A.C. Hannon; J.R. Plaisier

doi:10.1016/j.jnoncrysol.2013.12.023

Neutron and X-ray diffraction and empirical potential structure refinement modelling of magnesium stabilised amorphous calcium carbonate

G. Cobourne, G. Mountjoy^*, Juan Diego Rodriguez Blanco, L.G. Benning, A.C. Hannon, J.R. Plaisier

^*Corresponding author af dette arbejde

Kemisk Institut

17 Citationer (Scopus)

Abstract

Amorphous calcium carbonate (ACC) plays a key role in biomineralisation processes in sea organisms. Neutron and X-ray diffraction have been performed for a sample of magnesium-stabilised ACC, which was prepared with a Mg:Ca ratio of 0.05:1 and 0.25 H₂O molecules per molecule of CO₃. The empirical potential structure refinement method has been used to make a model of magnesium-stabilised ACC and the results revealed a fair agreement with the experimental diffraction data. The model has well-defined CO₃ and H₂O molecules. The average coordination number of Ca is 7.4 and is composed of 6.8 oxygen atoms from CO₃ molecules and 0.6 oxygen atoms from H₂O molecules. The average CaO bond length is 2.40 Å. The distribution of Ca in the model is homogeneous with a uniformly distributed Ca-rich network and no evidence of the Ca-poor channels as previously reported for a reverse Monte Carlo model of ACC.

Originalsprog	Engelsk
Tidsskrift	Journal of Non-Crystalline Solids
Vol/bind	401
Sider (fra-til)	154-158
Antal sider	5
ISSN	0022-3093
DOI	https://doi.org/10.1016/j.jnoncrysol.2013.12.023
Status	Udgivet - 2014

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10.1016/j.jnoncrysol.2013.12.023

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title = "Neutron and X-ray diffraction and empirical potential structure refinement modelling of magnesium stabilised amorphous calcium carbonate",

abstract = "Amorphous calcium carbonate (ACC) plays a key role in biomineralisation processes in sea organisms. Neutron and X-ray diffraction have been performed for a sample of magnesium-stabilised ACC, which was prepared with a Mg:Ca ratio of 0.05:1 and 0.25 H2O molecules per molecule of CO3. The empirical potential structure refinement method has been used to make a model of magnesium-stabilised ACC and the results revealed a fair agreement with the experimental diffraction data. The model has well-defined CO3 and H2O molecules. The average coordination number of Ca is 7.4 and is composed of 6.8 oxygen atoms from CO3 molecules and 0.6 oxygen atoms from H2O molecules. The average CaO bond length is 2.40 {\AA}. The distribution of Ca in the model is homogeneous with a uniformly distributed Ca-rich network and no evidence of the Ca-poor channels as previously reported for a reverse Monte Carlo model of ACC.",

keywords = "Amorphous calcium carbonate, EPSR modelling, Neutron diffraction, X-ray diffraction",

author = "G. Cobourne and G. Mountjoy and {Rodriguez Blanco}, {Juan Diego} and L.G. Benning and A.C. Hannon and J.R. Plaisier",

note = "STRUCTURE OF NON-CRYSTALLINE MATERIALS 12 Proceedings of the 12th International Conference on the Structure of Non-Crystalline Materials (NCM 12)",

year = "2014",

doi = "10.1016/j.jnoncrysol.2013.12.023",

language = "English",

volume = "401",

pages = "154--158",

journal = "Journal of Non-Crystalline Solids",

issn = "0022-3093",

publisher = "Elsevier BV * North-Holland",

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TY - JOUR

T1 - Neutron and X-ray diffraction and empirical potential structure refinement modelling of magnesium stabilised amorphous calcium carbonate

AU - Cobourne, G.

AU - Mountjoy, G.

AU - Rodriguez Blanco, Juan Diego

AU - Benning, L.G.

AU - Hannon, A.C.

AU - Plaisier, J.R.

N1 - STRUCTURE OF NON-CRYSTALLINE MATERIALS 12 Proceedings of the 12th International Conference on the Structure of Non-Crystalline Materials (NCM 12)

PY - 2014

Y1 - 2014

N2 - Amorphous calcium carbonate (ACC) plays a key role in biomineralisation processes in sea organisms. Neutron and X-ray diffraction have been performed for a sample of magnesium-stabilised ACC, which was prepared with a Mg:Ca ratio of 0.05:1 and 0.25 H2O molecules per molecule of CO3. The empirical potential structure refinement method has been used to make a model of magnesium-stabilised ACC and the results revealed a fair agreement with the experimental diffraction data. The model has well-defined CO3 and H2O molecules. The average coordination number of Ca is 7.4 and is composed of 6.8 oxygen atoms from CO3 molecules and 0.6 oxygen atoms from H2O molecules. The average CaO bond length is 2.40 Å. The distribution of Ca in the model is homogeneous with a uniformly distributed Ca-rich network and no evidence of the Ca-poor channels as previously reported for a reverse Monte Carlo model of ACC.

AB - Amorphous calcium carbonate (ACC) plays a key role in biomineralisation processes in sea organisms. Neutron and X-ray diffraction have been performed for a sample of magnesium-stabilised ACC, which was prepared with a Mg:Ca ratio of 0.05:1 and 0.25 H2O molecules per molecule of CO3. The empirical potential structure refinement method has been used to make a model of magnesium-stabilised ACC and the results revealed a fair agreement with the experimental diffraction data. The model has well-defined CO3 and H2O molecules. The average coordination number of Ca is 7.4 and is composed of 6.8 oxygen atoms from CO3 molecules and 0.6 oxygen atoms from H2O molecules. The average CaO bond length is 2.40 Å. The distribution of Ca in the model is homogeneous with a uniformly distributed Ca-rich network and no evidence of the Ca-poor channels as previously reported for a reverse Monte Carlo model of ACC.

KW - Amorphous calcium carbonate

KW - EPSR modelling

KW - Neutron diffraction

KW - X-ray diffraction

U2 - 10.1016/j.jnoncrysol.2013.12.023

DO - 10.1016/j.jnoncrysol.2013.12.023

M3 - Journal article

AN - SCOPUS:84905713117

SN - 0022-3093

VL - 401

SP - 154

EP - 158

JO - Journal of Non-Crystalline Solids

JF - Journal of Non-Crystalline Solids

ER -

Neutron and X-ray diffraction and empirical potential structure refinement modelling of magnesium stabilised amorphous calcium carbonate

Abstract

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