You are currently viewing the abstract.
View Full TextLog in to view the full text
AAAS login provides access to Science for AAAS members, and access to other journals in the Science family to users who have purchased individual subscriptions.
More options
Download and print this article for your personal scholarly, research, and educational use.
Buy a single issue of Science for just $15 USD.
Hydrous CaCO3 gets a new structure
Calcium carbonate (CaCO3) forms important minerals on Earth and is a model system for understanding crystal nucleation. Three different structures of CaCO3 are known, along with two structures that are hydrated. Zou et al. found a third hydrated CaCO3 structure formed from amorphous CaCO3 in the presence of magnesium ions. The discovery illustrates the importance of amorphous precursors for producing new materials.
Science, this issue p. 396
Abstract
As one of the most abundant materials in the world, calcium carbonate, CaCO3, is the main constituent of the skeletons and shells of various marine organisms. It is used in the cement industry and plays a crucial role in the global carbon cycle and formation of sedimentary rocks. For more than a century, only three polymorphs of pure CaCO3—calcite, aragonite, and vaterite—were known to exist at ambient conditions, as well as two hydrated crystal phases, monohydrocalcite (CaCO3·1H2O) and ikaite (CaCO3·6H2O). While investigating the role of magnesium ions in crystallization pathways of amorphous calcium carbonate, we unexpectedly discovered an unknown crystalline phase, hemihydrate CaCO3·½H2O, with monoclinic structure. This discovery may have important implications in biomineralization, geology, and industrial processes based on hydration of CaCO3.
This is an article distributed under the terms of the Science Journals Default License.
