Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published November 20, 1975 | public
Journal Article

Does metallic ammonium exist?

Abstract

The ammonium ion NH_4^+ behaves in many ways like an alkali metal ion. This led Ramsey to propose that monovalent ammonium metal (NH_4^+ ions immersed in an almost uniform, degenerate sea of electrons) is stable at pressures much lower than typical insulator–metal transition pressures of megabars ~10^(11) Pa (10^5 Pa = 1 bar). Subsequently, it was estimated that the transition from a mixture of NH_3 and H_2 molecules to metallic ammonium, occurs at a pressure of less than 2.5×10^(10) Pa. If this estimate were correct, metallic ammonium would be of great interest to experimental high pressure physicists, and to planetary physicists. Indeed, metallic ammonium has been invoked in some but not all models for the interiors of Uranus and Neptune; and its existence could be of importance for calculations of the interior magnetic fields of these planets.

Additional Information

© 1975 Nature Publishing Group. Received August 4; accepted September 30, 1975. Discussions with N. W. Ashcroft and J. A. Krumhansl are acknowledged, as is the support by grants from the US National Science Foundation and NASA.

Additional details

Created:
August 22, 2023
Modified:
October 25, 2023