Editing Ammonium (section)

== Metal ==
The ammonium cation has very similar properties to the heavier [[alkali metal]] cations and is often considered a close equivalent.<ref name = "Holleman&Wiberg">{{Holleman&Wiberg}}</ref><ref name="Stevenson" /><ref name="Bernal&Massey" /> Ammonium is expected to behave as a [[metal]] ({{chem2|[NH4]+}} ions in a sea of [[electrons]]) at very high pressures, such as inside [[giant planet]]s such as [[Uranus]] and [[Neptune]].<ref name="Stevenson">{{cite journal |last1=Stevenson |first1=D. J. |date=November 20, 1975 |title=Does metallic ammonium exist? |journal=[[Nature (journal)|Nature]] |volume=258 |issue= 5532|pages=222–223 |doi=10.1038/258222a0 |bibcode = 1975Natur.258..222S |s2cid=4199721 }}</ref><ref name="Bernal&Massey">{{cite journal |last1=Bernal |first1=M. J. M. |last2=Massey |first2=H. S. W. |date=February 3, 1954 |title=Metallic Ammonium |journal=[[Monthly Notices of the Royal Astronomical Society]] |volume=114 |issue= 2|pages=172–179 |bibcode=1954MNRAS.114..172B |doi=10.1093/mnras/114.2.172|doi-access=free }}</ref>

Under normal conditions, ammonium does not exist as a pure metal but does as an [[amalgam (chemistry)|amalgam]] (alloy with [[mercury (element)|mercury]]).<ref>{{cite journal |last1=Reedy |first1=J.H.|date=October 1, 1929|title=Lecture demonstration of ammonium amalgam |journal=Journal of Chemical Education |volume=6 |issue=10 |pages=1767 |doi=10.1021/ed006p1767|bibcode=1929JChEd...6.1767R}}</ref>