caa a22 4500 463217519 CHVBK 20180405153201.0 cr unu---uuuuu 170326e20071001xx s 000 0 eng 10.1007/s00269-007-0172-8 doi (NATIONALLICENCE)springer-10.1007/s00269-007-0172-8 BaCO3: high-temperature crystal structures and the Pmcn → R 3 m phase transition at 811°C [Elektronische Daten] [Sytle Antao, Ishmael Hassan] 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, α phase to a trigonal, R3m, β 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. Springer-Verlag, 2007 Barium carbonate nationallicence BaCO3 nationallicence Witherite nationallicence High-temperature structures nationallicence Phase transition nationallicence Rietveld refinements nationallicence Synchrotron radiation nationallicence Antao Sytle Advanced Photon Source, Argonne National Laboratory, 60439, Argonne, IL, USA aut Hassan Ishmael Department of Chemistry, University of the West Indies, Mona, Kingston 7, Jamaica aut Physics and Chemistry of Minerals Springer-Verlag 34/8(2007-10-01), 573-580 0342-1791 34:8<573 2007 34 269 https://doi.org/10.1007/s00269-007-0172-8 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00269-007-0172-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Antao Sytle Advanced Photon Source, Argonne National Laboratory, 60439, Argonne, IL, USA aut NATIONALLICENCE 700 1- Hassan Ishmael Department of Chemistry, University of the West Indies, Mona, Kingston 7, Jamaica aut NATIONALLICENCE 773 0- Physics and Chemistry of Minerals Springer-Verlag 34/8(2007-10-01), 573-580 0342-1791 34:8<573 2007 34 269 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer