ClO 3 - aq + ClO - aq 2 ClO 2 - aq The last member of this class of compounds, the perchlorate ion ClO 4 - , is made by electrolyzing solutions of the chlorate ion.
Fluorine, chlorine, bromine, iodine, and astatine definitely are halogens.
Chemistry of the Elements 2nd ed.
Contaminants, because they absorb more light and heat than the glass does, will create a hot spot on the bulb surface when the lamp is turned on.
Many of them are very toxic and bioaccumulate in humans, and have a very wide application range.
Element 117, tennessine, might have some properties in common with the other elements.
In Australia, numerous house fires each year are attributed to ceiling-mounted halogen downlights.
Breathing in chlorine at a concentration of 50 parts per million is highly dangerous.