Unprecedented metallic BiS phase from the binary Bi–S family revisited under extreme conditions of high pressure and high temperature.

The stabilities and phase evolutions of the binary Bi–S compounds are investigated by using synchrotron radiation X-ray diffraction in a diamond anvil cell in combination with laser heating technique. When it is heated to 1300 K at 32.6 GPa, Bi 2 S 3 decomposes into element S and a new BiS phase, which can be quenched to ambient conditions. The present results verify that cubic BiS, with an unprecedented stoichiometry and novel bonding characteristics, is at least metastable. It may shed new light on the fundamental sciences and potential technologies of the group V-VI binary compounds. • The stabilities and phase evolutions of the binary Bi-S compounds under extreme conditions are investigated in detail. • Advanced synchrotron radiation X-ray diffraction in combination with laser heating technique is used. • Bi 2 S 3 is thermodynamically unstable and decompose into a novel phase with an unprecedented BiS stoichiometry. • The present results verify that cubic BiS, with an unprecedented stoichiometry, is at least metastable. [ABSTRACT FROM AUTHOR]