Assertion: thorium | /r/AtLocation | two modifications
Facets:
Source sentences:
text: Thorium exists in two modifications: the α form, which has a face-centered cubic lattice and exists at temperatures up to 1400°C (a = 5.086 angstroms [Å]), and the β form, which has a body-centered cubic lattice and exists at temperatures above 1400°C (a = 4.11 Å).