Assertion: lr | /r/HasProperty | artificial element
Facets:
Source sentences:
text: Lawrencium is an artificial element and does not exist in nature and only is produced in a laboratory.
text: Lawrencium (Lr) is an artificial chemical element, atomic number 103, solid, metal, period 7, the last element in the actinoids family, radioactive, unstable, obtained by nuclear reactions in particles accelerators.