title: Vaterite crystals contain two interspersed crystal structures.
abstract: Calcite, aragonite, and vaterite are the three anhydrous polymorphs of calcium carbonate, in order of decreasing thermodynamic stability. Although vaterite is not commonly found in geological settings, it is an important precursor in several carbonate-forming systems and can be found in biological settings. Because of difficulties in obtaining large, pure, single crystals, the crystal structure of vaterite has been elusive for almost a century. Using aberration-corrected high-resolution transmission electron microscopy, we found that vaterite is actually composed of at least two different crystallographic structures that coexist within a pseudo-single crystal. The major structure exhibits hexagonal symmetry; the minor structure, existing as nanodomains within the major matrix, is still unknown.
authors.affiliation: Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Lee
authors.initials: L
authors.lastname: Kabalah-Amitai
authors.forename: Boaz
authors.initials: B
authors.lastname: Mayzel
authors.forename: Yaron
authors.initials: Y
authors.lastname: Kauffmann
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Fitch
authors.forename: Leonid
authors.initials: L
authors.lastname: Bloch
authors.forename: Pupa U P A
authors.initials: PU
authors.lastname: Gilbert
authors.forename: Boaz
authors.initials: B
authors.lastname: Pokroy