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On the structure of aragonite
1Physics Department, Nuclear Research Centre-Negev, PO Box 9001, Beer-Sheva 84190, Israel. caspie@nrcn.org.il
Acta Crystallographica. Section B, Structural Science
|March 18, 2005
Summary
High-resolution X-ray diffraction confirms pure geological aragonite, a calcium carbonate polymorph, exhibits orthorhombic symmetry. This study precisely determined aragonite lattice parameters using synchrotron powder diffraction.
Area of Science:
- Geochemistry
- Crystallography
- Materials Science
Background:
- Aragonite is a common polymorph of calcium carbonate (CaCO3) found in geological settings.
- Understanding its precise crystal structure is crucial for various scientific disciplines.
Purpose of the Study:
- To clarify the crystal structure of geological aragonite.
- To determine the lattice parameters of pure aragonite with high accuracy.
Main Methods:
- High-resolution synchrotron powder diffraction measurements were performed at the Advanced Photon Source.
- Wavelength-dispersive X-ray spectroscopy was used to ensure crystal purity.
- Rietveld refinement was applied to analyze the diffraction data.
Main Results:
- Superior quality diffraction data were obtained using a 11-channel Si multi-analyzer.
- Aragonite lattice parameters were extracted with an accuracy of approximately 20 parts per million (p.p.m.).
- The experimental data unambiguously confirmed the orthorhombic symmetry of pure aragonite crystals.
Conclusions:
- Pure geological aragonite crystals possess orthorhombic symmetry.
- The study provides highly accurate structural data for aragonite.
- This research refines our understanding of a fundamental geological material.