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Student Seminar: Chemistry Under Ultra-High Pressure: Insights from the case study of Sodium

by | Apr 15, 2025 | research | 0 comments

Student Seminar
 
Name: Mr. Shovik Ray
 
Title: Chemistry Under Ultra-High Pressure: Insights from the case study of Sodium
      Date & Time: Thursday, 17th April 2025 at 4.00 p.m. 
     Venue: Rajarshi Bhattacharya Memorial  Lecture Hall, Chemical Sciences Building
Abstract:  
The study of chemistry under ultra high-pressure conditions reveals fascinating transformations in the behavior of elements and compounds.1 This research explores the fundamental principles governing chemical bonding and structural evolution in dense solids subjected to extreme pressures, akin to those found in the interiors of giant planets and stars. At such high pressures, transitions from molecular to extended covalent, ionic, and metallic solids occur, highlighting novel properties and complex mechanisms that emerge. In the laboratory, we generate and apply these immense pressures (>500 GPa ≈ 1011 atm) using Diamond Anvil Cell (DAC) and characterize the phase changes of materials primarily through X-ray diffraction (XRD), and Raman scattering.
In this talk, I will explore ultra high-pressure setups and their practical implementations, using a case study of sodium (Na) to illustrate these concepts.2-4 When subjected to pressures exceeding 200 GPa, sodium undergoes a remarkable transformation from a shiny, metallic conductor to a transparent, insulating phase.4 This transition challenges conventional understanding by involving the reorganization of electrons and the formation of new chemical bonds
References:
  1. 1. Grochala, W.; Hoffmann, R.; Feng, J.; Ashcroft, N. W. The Chemical Imagination at Work in Very Tight Places. Angew. Chem. Int. Ed. 2007, 46 (20), 3620-3642.
  1. 2. Sahu, P. Ch.; Chandra Shekar, N. V. Production and Measurement of High Pressures in the Laboratory. Resonance 2007, 12 (6), 49-64.
  1. 3. Gregoryanz, E.; Lundegaard, L. F.; McMahon, M. I.; Guillaume, C.; Nelmes, R. J.; Mezouar, M. Structural transformations in sodium under pressure. Science 2008, 320 (5879), 1054-1057.
  1. 4. Ma, Y.; Eremets, M.; Oganov, A. R.; Xie, Y.; Trojan, I.; Medvedev, S.; Lyakhov, A. O.; Valle, M.; Prakapenka, V. Transparent dense sodium. Nature 2009, 458 (7235), 182-185.