dioksid

Dioksid, or dioxide, is a term used in chemistry to designate compounds that contain two oxygen atoms per formula unit. The name is used in several languages (for example dioxide in English, dioksid/dioksida in others) and commonly refers to binary oxides of varying elements. The most familiar example is carbon dioxide, CO2, a colorless gas produced by respiration and combustion and a significant greenhouse gas.

Many dioxides are formed when oxygen combines with another element in a two-to-one ratio. Other well-known dioxides include sulfur dioxide (SO2), a gas produced by burning sulfur-containing fuels and certain industrial processes; silicon dioxide (SiO2), a major component of sand, quartz, and glass; and titanium dioxide (TiO2), a widely used white pigment in paints, plastics, and sunscreens. Some metal dioxides exist as solid oxides with various crystal structures, such as tin(IV) oxide (SnO2) and zirconium dioxide (ZrO2), which have widespread industrial applications.

Properties of dioxides vary widely. Some are gases at room temperature (CO2, SO2), while others are solids (SiO2, TiO2). Many are acidic oxides and react with water to form corresponding acids (for example CO2 forms carbonic acid in water; SO2 forms sulfites and sulfurous acid). Production and occurrence also differ: CO2 is released during respiration and combustion; SO2 arises from burning sulfur-containing fuels and some mining processes; SiO2 is abundant in the Earth's crust; TiO2 is produced commercially from titanium-containing minerals.

Uses and safety: CO2 serves as a beverage additive and chemical feedstock but is a climate concern in the atmosphere. SO2 has uses in food preservation and paper bleaching but can contribute to acid rain and respiratory irritation. SiO2 and TiO2 have extensive industrial applications; inhalation of fine oxide dusts can pose health risks, so appropriate controls are recommended.