二氧化硫

The number two; second in order; twice; a pair; dual; also used as a variant of 'to change' or 'to compare'.

Oxygen; the chemical element O, essential for respiration and combustion; found naturally in the air.

To change or transform; to make into; to convert; to dissolve; to die; suffix indicating -ization or -ize.

Sulfur; the chemical element S, a nonmetal element that is a pale yellow crystalline solid; used in making sulfuric acid, gunpowder, matches, and insecticides.