caa a22 4500 46321742X CHVBK 20180405153201.0 cr unu---uuuuu 170326e20070501xx s 000 0 eng 10.1007/s00269-007-0141-2 doi (NATIONALLICENCE)springer-10.1007/s00269-007-0141-2 In situ neutron diffraction study of deuterated portlandite Ca(OD)2 at high pressure and temperature [Elektronische Daten] [Hongwu Xu, Yusheng Zhao, Jianzhong Zhang, Donald Hickmott, Luke Daemen] The structure of deuterated portlandite, Ca(OD)2, has been investigated using time-of-flight neutron diffraction at pressures up to ∼4.5GPa and temperatures up to ∼823K. Rietveld analysis of the data reveals that with increasing pressure, unit-cell parameter c decreases at a rate about 4.5 times larger than that for a, which is largely due to rapid contraction of the interlayer spacing in this pressure range. Fitting of the determined cell volumes to the third-order Birch-Murnaghan equation of state yields a bulk modulus (K 0) of 32.2±1.0GPa and its first derivative (K 0′) of 4.4±0.6. Moreover, on compression, hydrogen-mediated interatomic interactions within the interlayer become strengthened, as reflected by decreases in interlayer D···O and D···D distances with increasing pressure. Correspondingly, D-D, the distance between the three equivalent sites over which D is disordered, increases, suggesting a pressure-induced hydrogen disorder. This behavior is similar to that reported in brucite at elevated pressure. On heating at ∼2.1GPa, cell parameter c increases more rapidly than a, as expected. However, because of the pressure effect, the thermal expansion coefficients, particularly along c, are much smaller than those at ambient pressure. With increasing temperature, the three partially occupied D sites become further apart, and the D-mediated interactions, mainly the interlayer D···D repulsion, become weakened. Springer-Verlag, 2007 Portlandite nationallicence Crystal structure nationallicence Equation of state nationallicence Bulk modulus nationallicence Thermal expansion coefficient nationallicence Neutron diffraction nationallicence Xu Hongwu Earth and Environmental Sciences Division, Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut Zhao Yusheng Los Alamos Neutron Science Center, Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut Zhang Jianzhong Los Alamos Neutron Science Center, Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut Hickmott Donald Earth and Environmental Sciences Division, Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut Daemen Luke Los Alamos Neutron Science Center, Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut Physics and Chemistry of Minerals Springer-Verlag 34/4(2007-05-01), 223-232 0342-1791 34:4<223 2007 34 269 https://doi.org/10.1007/s00269-007-0141-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00269-007-0141-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Xu Hongwu Earth and Environmental Sciences Division, Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut NATIONALLICENCE 700 1- Zhao Yusheng Los Alamos Neutron Science Center, Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut NATIONALLICENCE 700 1- Zhang Jianzhong Los Alamos Neutron Science Center, Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut NATIONALLICENCE 700 1- Hickmott Donald Earth and Environmental Sciences Division, Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut NATIONALLICENCE 700 1- Daemen Luke Los Alamos Neutron Science Center, Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut NATIONALLICENCE 773 0- Physics and Chemistry of Minerals Springer-Verlag 34/4(2007-05-01), 223-232 0342-1791 34:4<223 2007 34 269 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer