High-temperature single-crystal neutron diffraction study ofnatural chondrodite
The H-atom environment in a Tilly Foster chondrodite wasanalyzed using single-crystal neutron-diffraction data collected at 500,700 and 900 K and previously published low temperature data collected at10 K, 100 K and 300 K on the same crystal(Mg4.64Fe0.28Mn0.014Ti0.023(Si1.01O4)2F1.16OH0.84, Friedrich et al.2001). The full mean square displacement matrix S of the O-H pair wasdetermined from the temperature dependence of the anisotropicdisplacement parameters, enabling a proper correction of the O-H bond forthermal vibration without assumptions about the correlation of O and Hmovements. The results show that the perpendicular O-H motions inchondrodite are intermediate between the riding and the independentmotion models. The corrected O-H bond lengths do not change withtemperature whereas the corrected H...F distances show an increase of~;0.02 Angstrom with temperature, as do the Mg-O distances. This resultshows that spectroscopic observations on the strength of the covalent O-Hbond cannot be interpreted unambiguously in terms of a correspondingbehaviour of the associated H...O/F hydrogen bond.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Basic EnergySciences
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 919815
- Report Number(s):
- LBNL-59075; PCMIDU; R&D Project: A58189; BnR: KC0204016; TRN: US200822%%565
- Journal Information:
- Physics and Chemistry of Minerals, Vol. 33, Issue 1; Related Information: Journal Publication Date: March 2006; ISSN 0342-1791
- Country of Publication:
- United States
- Language:
- English
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