allotropy

n.

同素异形（现象）；

1. Polymorphism in elements is called allotropy.
   把元素中的多晶现象称为同素异构性。

ALLOTROPY IN HAFNIUM OXIDE UNDER HIGH PRESSURE
Allotropy in Some Rare-Earth Metals at High Pressures
Atomic volume and allotropy of the elements
Isomorphism and allotropy in compounds of the type A_2XO_4
Viscous Flow and Melt Allotropy of Phosphorus Pentoxide
THE HIGH-TEMPERATURE ALLOTROPY OF SOME HEAVY RARE-EARTH METALS
High temperature allotropy and thermal expansion of the rare-earth metals ☆
An extensive theoretical survey of low-density allotropy in silicon.
Carbene stabilization of diarsenic: from hypervalency to allotropy
Physical Properties of Polonium. I. Melting Point, Electrical Resistance, Density, and Allotropy