University Park, PA 16802, USA
c School of Engineering, Brown University,
Providence, RI 02912, USA
Corresponding
author: xuc83@psu.edu (X.Y.
Chong)
Abstract :
Calcium
carbonate (CaCO3) is an inorganic compound which is
widely used in industry, chemistry, construction, ocean acidification
and biomineralization due to its rich constituent on earth and excellent
performance, in which calcium carbonate hydrates are important systems.
In Z.Y. Zou et al’s work (Science , 2019, 363, 396–400), they
found a novel calcium carbonate hemihydrate phase, but the structure
stability, optical and mechanical properties has not been studied. In
this work, the stability, electronic, optical, and mechanical properties
of novel calcium carbonate hydrates were investigated by using the
first-principles calculations within density functional theory (DFT).
CaCO3·x H2O
(x= 1/2, 1 and 6) are determined dynamically stable phases by
phonon spectrum, but the Gibbs energy of reaction of
CaCO3·1/2H2O is higher than other
calcium carbonate hydrates. That’s why the
CaCO3·1/2H2O is hard to synthesize in
the experiments.
In
addition, the optical and mechanical properties of
CaCO3·x H2O (x= 1/2, 1 and
6) are expounded in detail. It shows that the
CaCO3·1/2H2O has the largest bulk
modulus, shear modulus, Young’s modulus with the values 60.51, 36.56 and
91.28 GPa with respect to other two calcium carbonate hydrates
investigated in this paper. This work will provide guidance for
experiments and its applications, such as biomineralization, geology,
and industrial processes.
Keywords:First-principles
calculations; Calcium carbonate hydrates; Phonon; Optical properties;
Mechanical properties