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The structural behaviour of Pm metal has been investigated up to 60 GPa using a DAC and the energy dispersive X-ray diffraction technique. The room temperature/pressure structural form of promethium is dhcp and it transforms to a fcc structure by 10 GPa. By 18 GPa this cubic form of the metal converts to a third form, which has frequently been thought to represent a distorted fcc structure. This is retained up to 60 GPa, the maximum pressure studied. Subtle changes in the X-ray spectra between 50 and 60 GPa suggest that an additional structural change may be forthcoming at higher pressures. From the experimental data a bulk modulus B(o) of 38 GPa and a B(o') constant of 1.5 were obtained for the Birch equation. This modulus for Pm is in accord with the moduli reported for the neighbouring lanthanide metals.

Additional information

Authors: HAIRE R G, Oak Ridge National Laboratory, Tennessee (US);HEATHMAN S, JRC Karlsruhe (DE);BENEDICT U, JRC Karlsruhe (DE)
Bibliographic Reference: Paper presented: 3rd Workshop "Actinides under Pressure", Karlsruhe (DE), July 24-25, 1989
Availability: Available from (1) as Paper EN 35087 ORA
Record Number: 199011018 / Last updated on: 1994-12-01
Original language: en
Available languages: en