Toxic form of oxygen, symbol O3 (5)
I believe the answer is:
ozone
(Other definitions for ozone that I've seen before include "Sea air; bleaching agent" , "Protection" , "Shield against radiation" , "Colourless gas, O3" , "It's said to brace" .)
I believe the answer is:
ozone
(Other definitions for ozone that I've seen before include "Sea air; bleaching agent" , "Protection" , "Shield against radiation" , "Colourless gas, O3" , "It's said to brace" .)