Related Experiment Video
Updated: Sep 24, 2025

High-Pressure NMR Experiments for Detecting Protein Low-Lying Conformational States
Published on: June 29, 2021
Pressure-induced phase transition of 1,5-diamino-1H-tetrazole (DAT) under high pressure
Cheng Jin1, Ying Liu2, Lijuan Wang1
1Center for High Pressure Science and Technology Advanced Research (HPSTAR) Beijing 100094 China zhujl@sustech.edu.cn.
Abstract:
Nitrogen-rich energetic materials have attracted certain interest as promising high energy density materials (HEDMs) in recent years. Pure N2 and nitrogen-based molecular crystals are ideal HEDMs that would polymerize under high pressure, as reported in previous literature. We selected a 1,5-diamino-1H-tetrazole (DAT) crystal, which has two kinds of molecular structures and hydrogen bonds, to study under high pressure by spectroscopy and diffraction due to its high nitrogen percentage and low sensitivities. Pressure-induced structure transitions occur at pressures of 2.3-6.6 GPa, ∼8.5 GPa, and ∼17.7 GPa. The phase transition at 2.3-6.6 GPa is related to the rotation of NH2, and the latter two transitions are caused by both the rotation of NH2 and the distortion of the heterocycle. Significantly, the reconstitution of the hydrogen bond may induce the rotation/distortion of the NH2/heterocycle in the second phase transition. There is no evidence showing a transformation between the two molecular structures in the whole pressure range studied. Our investigation uncovers the phase transition mechanism of DAT under pressure, which will help to find targeted HEDMs.
More Related Videos
08:42High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extreme Conditions
Published on: October 10, 2014
07:26Synthesis and Microdiffraction at Extreme Pressures and Temperatures
Published on: October 7, 2013
Related Concept Videos
Phase Diagram
Phase Transitions
Phase Diagrams
Phase Changes
A substance melts or freezes at a temperature called its melting point and boils or condenses at its boiling point. These temperatures depend on pressure. High pressure favors the denser form of the substance, so typically, high pressure...
Phase Transitions: Sublimation and Deposition
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR