Short-Range Structure of Amorphous Calcium Hydrogen Phosphate
MetadataShow full item record
Funding and Sponsorship
This document is the Accepted Manuscript version of a Published Work that appeared in final form in Crystal Growth and Design, copyright © American Chemical Society, after peer review and technical editing by the publisher. To access the final edited and published work see http://doi.org/10.1021/acs.cgd.9b00274
Copyright © 2019 American Chemical Society. Calcium orthophosphates (CaPs) are the hard constituents of bones and teeth, and thus of ultimate importance to humankind, while amorphous CaPs (ACPs) may play crucial roles in CaP biomineralization. Among the various ACPs with Ca/P atomic ratios between 1.0-1.5, an established structural model exists for basic ACP (Ca/P = 1.5), while those of other ACPs remain unclear. Herein, the structure of amorphous calcium hydrogen phosphate (ACHP; Ca/P = 1.0) obtained via aqueous routes at near-neutral pH values, without stabilizers, was studied by experiments (mainly, TEM with ED, XRD, IR, and NMR spectroscopies, as well as XAS) and computer simulation. Our results globally show that ACHP has a distinct short-range structure, and we propose calcium hydrogen phosphate clusters (CHPCs) as its basic unit. This model is consistent with both computer simulations and the experimental results, where CHPCs are arranged together with water molecules to build up ACHP. We demonstrate that Posner's clusters, which are conventionally accepted to be the building unit of basic ACPs, do not represent the short-range structure of ACHP, as Posner's clusters and CHPCs are structurally distinct. This finding is important not only for the determination of the structures of diverse ACPs with varying Ca/P atomic ratios but also for fundamental understanding of a major mineral class that is central to biomineralization in vertebrates and, thus, humans, in particular. ©
Showing items related by title, author, creator and subject.
The role of grain boundaries and transient porosity in rocks as fluid pathways for reaction front propagationJonas, L.; John, T.; King, H.; Geisler, T.; Putnis, Andrew (2014)The pseudomorphic replacement of Carrara marble by calcium phosphates was used as a model system in order to study the influence of different fluid pathways for reaction front propagation induced by fluid–rock interaction. ...
Urolithiasis: occurrence and function of intracrystalline proteins in calcium oxalate monohydrate crystalsFleming, David Elliot (2004)The broad aim of the work presented in this thesis was to examine the relationship between the mineral and organic phases of calcium oxalate monohydrate (COM) crystals, which are the principal components of human kidney ...
Demichelis, R.; Garcia, N.; Raiteri, Paolo; Innocenti Malini, R.; Freeman, C.; Harding, J.; Gale, Julian (2017)A new force field has been derived for the aqueous calcium phosphate system that aims to reproduce the key thermodynamic properties of the system, including free energies of hydration of the ions and the solubility of the ...