Crystal structure of the high pressure phase of antimony SbII

Abstract

Crystal structure of the post-A7 phase of antimony, named SbII, has been determined at a pressure of 12 GPa using powdered samples squeezed in a diamond-anvil cell by X-ray diffraction on synchrotron and laboratory sources. It has been shown that the structure is tetragonal, space group P4/n, with 10 atoms in a unit cell of the sizes of a=0.7965 nm and c= 0.3857 nm. The atomic arrangement can be regarded as a distorted body-centered tetragonal structure with each atom surrounded by 8 nearest neighbors. The structure of SbII is just an intermediate between the A7 structure of SbI with a small deviation from the primitive simple cubic one and the body-centered cubic structure of SbIII.

Key Words:

• Antimony
• high pressure structure
• high pressure phase transition
• Group Vb element