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Title: Geometrically frustrated interactions drive structural complexity in amorphous calcium carbonate
Abstract Amorphous calcium carbonate is an important precursor for biomineralization in marine organisms. Key outstanding problems include understanding the structure of amorphous calcium carbonate and rationalizing its metastability as an amorphous phase. Here we report high-quality atomistic models of amorphous calcium carbonate generated using state-of-the-art interatomic potentials to help guide fits to X-ray total scattering data. Exploiting a recently developed inversion approach, we extract from these models the effective Ca⋯Ca interaction potential governing the structure. This potential contains minima at two competing distances, corresponding to the two different ways that carbonate ions bridge Ca2+-ion pairs. We reveal an unexpected mapping to the Lennard-Jones–Gauss model normally studied in the context of computational soft matter. The empirical model parameters for amorphous calcium carbonate take values known to promote structural complexity. We thus show that both the complex structure and its resilience to crystallization are actually encoded in the geometrically frustrated effective interactions between Ca2+ions.  more » « less
Award ID(s):
1652237
PAR ID:
10467711
Author(s) / Creator(s):
; ; ; ; ; ; ;
Publisher / Repository:
Nature Chemistry
Date Published:
Journal Name:
Nature Chemistry
ISSN:
1755-4330
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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