Editing Allotropy (section)

====Lanthanides and actinides====
[[File:Actinide phases.svg|right|thumb|250px|Phase diagram of the actinide elements.]]

* [[Cerium#Characteristics|Cerium]], [[Samarium#Physical properties|samarium]], [[Dysprosium#Characteristics|dysprosium]] and [[Ytterbium#Characteristics|ytterbium]] have three allotropes.
* [[Praseodymium#Characteristics|Praseodymium]], [[Neodymium#Characteristics|neodymium]], [[Gadolinium#Characteristics|gadolinium]] and [[Terbium#Characteristics|terbium]] have two allotropes.
* [[Allotropes of plutonium|Plutonium]] has six distinct solid allotropes under "normal" pressures. Their densities vary within a ratio of some 4:3, which vastly complicates all kinds of work with the metal (particularly casting, machining, and storage). A seventh plutonium allotrope exists at very high pressures. The [[Transuranium element|transuranium]] metals Np, Am, and Cm are also allotropic.
* [[Promethium#Properties|Promethium]], [[americium]], [[berkelium]] and [[californium]] have three allotropes each.<ref>{{cite journal|doi=10.1088/0305-4608/15/2/002|title=Delocalisation of 5f electrons in curium metal under high pressure|journal=Journal of Physics F: Metal Physics|volume=15|issue=2|pages=L29–L35|year=1985|last1=Benedict|first1=U.|last2=Haire|first2=R. G.|last3=Peterson|first3=J. R.|last4=Itie|first4=J. P.|bibcode=1985JPhF...15L..29B}}</ref>