Related Experiment Video
Updated: Feb 20, 2026
10:28
Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy
Published on: May 27, 2018
9.5K
Topologically frustrated ionisation in a water-ammonia ice mixture
C Liu1,2, A Mafety1, J A Queyroux1
1Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Universités-UPMC Univ. Paris 6, CNRS UMR 7590, IRD UMR 206, MNHN, 4 Place Jussieu, F-75005, Paris, France.
Nature Communications
|October 21, 2017
Summary
Ammonia monohydrate transforms into a mix of neutral and ionic species at moderate pressures. This study reveals unique high-pressure behavior of water and ammonia mixtures, crucial for understanding icy planet interiors.
Area of Science:
- Planetary Science
- Materials Science
- Physical Chemistry
Background:
- Water and ammonia are key components in icy planet interiors.
- High pressures reveal exotic phases of pure water and ammonia ices.
Purpose of the Study:
- Investigate the high-pressure properties of ammonia monohydrate.
- Understand the phase behavior of equimolar water-ammonia mixtures.
Main Methods:
- Experimental study of ammonia monohydrate under high P-T conditions.
- Ab initio atomistic simulations to model phase behavior.
Main Results:
- Ammonia monohydrate transforms at 7.4 GPa and 300 K.
- Coexistence of neutral water/ammonia with hydroxide and ammonium ions observed.
- Topological frustration explains the neutral/ionic species coexistence.
Conclusions:
- Mild pressures induce significant chemical changes in ammonia monohydrate.
- The findings provide insights into the interior composition of icy celestial bodies.
- This work highlights complex ionisation mechanisms in planetary ices.
Related Concept Videos
03:13Intermolecular Forces
73.3K
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen...
73.3K
01:21Chemical Ionization (CI) Mass Spectrometry
1.6K
The molecular ion peak of a molecule in the mass spectrum provides vital information for molecular identification. However, conventional electron impact ionization can lead to the rapid dissociation of some molecular ions before they reach the detector. A milder ionization method is required to increase the lifetime of such ionized analyte molecules. Chemical ionization (CI) is a gas-phase protonation reaction useful for mass-analyzing analyte molecules that are easily protonated to yield the...
1.6K
03:24Common Ion Effect
47.2K
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Châtelier’s principle. Consider the dissolution of silver iodide:
47.2K
02:30Water: A Bronsted-Lowry Acid and Base
59.6K
The reaction between a Brønsted-Lowry acid and water is called acid ionization. For example, when hydrogen fluoride dissolves in water and ionizes, protons are transferred from hydrogen fluoride molecules to water molecules, yielding hydronium ions and fluoride ions:
59.6K
02:42Aqueous Solutions and Heats of Hydration
18.3K
Water and other polar molecules are attracted to ions. The electrostatic attraction between an ion and a molecule with a dipole is called an ion-dipole attraction. These attractions play an important role in the dissolution of ionic compounds in water.
When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them. This process...
When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them. This process...
18.3K
03:38Polyprotic Acids
32.3K
Acids are classified by the number of protons per molecule that they can give up in a reaction. Acids such as HCl, HNO3, and HCN that contain one ionizable hydrogen atom in each molecule are called monoprotic acids. Their reactions with water are:
32.3K