Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

BaCO3: High-Temperature crystal Structures and the Pmcn → R3m Phase Transition at 811 Celius

Journal Article · · Physics and Chemistry of Minerals

The temperature (T) evolution of the barium carbonate (BaCO3) structure was studied using Rietveld structure refinements based on synchrotron X-ray diffraction and a powdered synthetic sample. BaCO3 transforms from an orthorhombic, Pmcn, a phase to a trigonal, R3m, {beta} phase at 811 C. The orthorhombic BaCO3 structure is isotypic with aragonite, CaCO3. In trigonal R3m BaCO3, the CO3 group occupies one orientation and shows no rotational disorder. The average <Ba-O> distances increase while the <C-O> distances decrease linearly with T in the orthorhombic phase. After the 811 C phase transition, the <Ba-O> distances increase while C-O distances decrease. There is also a significant volume change of 2.8% at the phase transition.

Research Organization:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Organization:
Doe - Office Of Science
DOE Contract Number:
AC02-98CH10886
OSTI ID:
959947
Report Number(s):
BNL--82933-2009-JA
Journal Information:
Physics and Chemistry of Minerals, Journal Name: Physics and Chemistry of Minerals Vol. 34; ISSN 0342-1791; ISSN PCMIDU
Country of Publication:
United States
Language:
English