Assertion: ozone | /r/HasProperty | discovered in 19th century
Facets:
value: originally
type: DEGREE
Source sentences:
text: Originally discovered in the 19th Century, ozone, a form of activated oxygen generally produced during lighting storms and continuously occurring in the stratosphere due to the action of ultraviolet (UV) rays, is being rediscovered in the 21st century.
text: Ozone is a colorless gas discovered in the 19th century, that consists of 3 oxygen atoms in an unstable structure due to the presence of mesomeric states.