caa a22 4500 463217462 CHVBK 20180405153201.0 cr unu---uuuuu 170326e20070501xx s 000 0 eng 10.1007/s00269-006-0140-8 doi (NATIONALLICENCE)springer-10.1007/s00269-006-0140-8 Ono Shigeaki Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka-shi, 237-0061, Kanagawa, Japan aut New high-pressure phases in BaCO3 [Elektronische Daten] [Shigeaki Ono] Barium carbonate (BaCO3) was examined in a diamond anvil cell up to a pressure of 73GPa using an in situ angle-dispersive X-ray diffraction technique. Three new phases of BaCO3 were observed at pressures >10GPa. From 10 to 24GPa, BaCO3-IV had a post-aragonite structure with space group Pmmn. There are two molecules in a single unit cell (Z=2) of the orthorhombic phase, which is same as the high-pressure phases of CaCO3 and SrCO3. The isothermal bulk modulus of BaCO3-IV is K 0=84(4)GPa, with V 0=129.0(7)Å3 when K 0′=4. The c axis of the unit cell parameter is less compressible than the a and b axes. The relative change in volume that accompanies the transformation between BaCO3-III and BaCO3-IV is ∼6%. BaCO3-V, which has an orthorhombic symmetry, was synthesized at 50GPa. As the pressure increases, BaCO3-V is transformed into tetragonal BaCO3-VI. This transformation is likely to be second order, because the diffraction pattern of BaCO3-V is similar to that of BaCO3-VI, and some single peaks in BaCO3-VI become doublets in BaCO3-V. After decompression, the new high-pressure phases transform into BaCO3-II. Our findings resolve a dispute regarding the stable high-pressure phases of BaCO3. Springer-Verlag, 2007 Barium carbonate nationallicence Phase transformation nationallicence Equation of state nationallicence High pressure nationallicence Diamond anvil cell nationallicence Physics and Chemistry of Minerals Springer-Verlag 34/4(2007-05-01), 215-221 0342-1791 34:4<215 2007 34 269 https://doi.org/10.1007/s00269-006-0140-8 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00269-006-0140-8 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Ono Shigeaki Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka-shi, 237-0061, Kanagawa, Japan aut NATIONALLICENCE 773 0- Physics and Chemistry of Minerals Springer-Verlag 34/4(2007-05-01), 215-221 0342-1791 34:4<215 2007 34 269 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer