Prof. Konstantin Glazyrin [PETRA III, DESY, Germany]

Title: High-pressure reactions between the pnictogens: the rediscovery of BiN

Language:  English presentation

Time: Beijing, 10:00 - 11:30 AM, Monday, September 23, 2024

Place:  Onsite：Conference room A417, HPSTAR (Beijing)            

            Online:  Tencent Meeting: https://meeting.tencent.com/dm/SxnGPnJ1km11 Meeting ID: 441-152-742

Host:  Prof. Chuanlong Lin

Abstract:

We investigate chemical reactions within pnictogens, using the interaction between bismuth and nitrogen under extreme conditions as an example. The understanding of chemical reactions between Bi and N, which represent the first and last stable elements of the nitrogen group, along with the physical properties of their compounds under ambient and high pressure, remains incomplete. In this study, we report the high-pressure, high-temperature synthesis of orthorhombic Pbcn BiN (S.G. #60) from Bi and N₂ precursors at pressures exceeding 40 GPa. Through synchrotron single-crystal X-ray diffraction on a polycrystalline sample, we determined and refined the structure of the compound, while analyzing its behavior and compressibility upon decompression to ambient pressure. Our findings confirm the stability of Pbcn BiN at pressures down to 12.5(4) GPa. Below this pressure, a group–subgroup phase transformation occurs, resulting in the formation of a non-centrosymmetric BiN phase with the space group Pca21 (S.G. #29). Ab initio calculations were employed to characterize the BiN polymorphs, providing insights into the experimental observations, particularly the unusual evolution of Bi–N bonds under pressure, which leads to changes in the coordination numbers of Bi and N across the stability field of Pbcn BiN.

Biography of the Speaker:

Konstantin Glazyrin, Beamline Operation Manager at the Extreme Conditions Beamline P02.2 (PETRA III, DESY, Hamburg, Germany). He received his Ph.D. degree in 2011 from the Bayerisches Geoinstitut in Bayreuth, Germany. After joining DESY in 2013, he became permanent beamline staff of P02.2 in 2017. In 2020, he completed the habilitation process at the Laboratory of Crystallography at the University of Bayreuth in Germany. His research fields include crystallography, novel chemistry, solid-state physics, and critical physical phenomena under high-pressure conditions.