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Title: Crystal structures of tricalcium citrates

Abstract

The crystal structures of calcium citrate hexahydrate, calcium citrate tetrahydrate, and anhydrous calcium citrate have been solved using laboratory and synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Both the hexahydrate and tetrahydrate structures are characterized by layers of edge-sharing Ca coordination polyhedra, including triply chelated Ca. An additional isolated Ca is coordinated by water molecules, and two uncoordinated water molecules occur in the hexahydrate structure. The previously reported polymorph of the tetrahydrate contains the same layers, but only two H 2O coordinated to the isolated Ca and two uncoordinated water molecules. Anhydrous calcium citrate has a three-dimensional network structure of Ca coordination polyhedra. The new polymorph of calcium citrate tetrahydrate is the major crystalline phase in several commercial calcium supplements.

Authors:
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
DOE - BASIC ENERGY SCIENCES
OSTI Identifier:
1459965
Resource Type:
Journal Article
Resource Relation:
Journal Name: Powder Diffraction; Journal Volume: 33; Journal Issue: 02
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Kaduk, James A. Crystal structures of tricalcium citrates. United States: N. p., 2018. Web. doi:10.1017/S0885715618000283.
Kaduk, James A. Crystal structures of tricalcium citrates. United States. doi:10.1017/S0885715618000283.
Kaduk, James A. Fri . "Crystal structures of tricalcium citrates". United States. doi:10.1017/S0885715618000283.
@article{osti_1459965,
title = {Crystal structures of tricalcium citrates},
author = {Kaduk, James A.},
abstractNote = {The crystal structures of calcium citrate hexahydrate, calcium citrate tetrahydrate, and anhydrous calcium citrate have been solved using laboratory and synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Both the hexahydrate and tetrahydrate structures are characterized by layers of edge-sharing Ca coordination polyhedra, including triply chelated Ca. An additional isolated Ca is coordinated by water molecules, and two uncoordinated water molecules occur in the hexahydrate structure. The previously reported polymorph of the tetrahydrate contains the same layers, but only two H2O coordinated to the isolated Ca and two uncoordinated water molecules. Anhydrous calcium citrate has a three-dimensional network structure of Ca coordination polyhedra. The new polymorph of calcium citrate tetrahydrate is the major crystalline phase in several commercial calcium supplements.},
doi = {10.1017/S0885715618000283},
journal = {Powder Diffraction},
number = 02,
volume = 33,
place = {United States},
year = {Fri Jun 01 00:00:00 EDT 2018},
month = {Fri Jun 01 00:00:00 EDT 2018}
}