Abstract
Bi-IV is the stable high-pressure, high-temperature phase of bismuth at similar to 4 GPa and similar to 500 K. It was first identified in 1958, but its structure has remained uncertain. An X-ray powder-diffraction study of Bi-IV reported the structure as monoclinic, but a subsequent reinterpretation of the same data concluded that the structure was C-centred orthorhombic (oC16), with the same atomic arrangement as in Cs-V and Si-VI. To resolve the uncertainty over the structure of Bi-IV, we investigated this phase at 3.2 GPa and 465 K by single-crystal synchrotron X-ray diffraction. All of the observed reflections could be indexed on the orthorhombic oC16 structure proposed by Degtyareva, with a = 11.191(5)angstrom, b = 6.622(1)angstrom and c = 6.608(1)angstrom. The spacegroup was confirmed as Cmce. Refinement of the data resulted in an excellent fit (R = 2.8%), and gave atomic coordinates very similar to those of the oC16 structures in Cs-V and Si-VI.
Original language | English |
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Pages (from-to) | 442-449 |
Number of pages | 8 |
Journal | High Pressure Research |
Volume | 32 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2012 |
Keywords / Materials (for Non-textual outputs)
- bismuth
- crystal structure
- high-pressure
- high temperature
- X-ray diffraction
- BISMUTH
- PHASE
- ANVIL
- POLYMORPHISM
- ELEMENTS
- METALS
- KBAR
- RUBY
- CELL
- VI