The functional groups that contain two oxygen atoms are called peroxides and organic peracids. These groups are important in organic chemistry as they exhibit unique chemical properties and reactivity due to the presence of two oxygen atoms.

Peroxides:
Peroxides are functional groups that contain an oxygen-oxygen single bond (O-O). They are represented by the general formula R-O-O-R', where R and R' can be any organic group. Peroxides are highly reactive compounds and can undergo various chemical reactions such as decomposition, oxidation, and reduction.

Organic Peracids:
Organic peracids are functional groups that contain both a carboxyl group (COOH) and a peroxide group (O-O). They are represented by the general formula R-COOOH, where R is an organic group. Organic peracids are powerful oxidizing agents and have applications in organic synthesis and bleaching.

Key Points:
- Peroxides contain an oxygen-oxygen single bond (O-O).
- Organic peracids contain both a carboxyl group (COOH) and a peroxide group (O-O).
- Peroxides are highly reactive and can undergo various chemical reactions.
- Organic peracids are powerful oxidizing agents.
- Both peroxides and organic peracids have applications in organic synthesis and bleaching.

Chemical Reactions:
1. Decomposition: Peroxides can easily decompose to form oxygen gas and the corresponding organic compound. For example, hydrogen peroxide (H2O2) decomposes into water (H2O) and oxygen (O2).
2H2O2 -> 2H2O + O2

2. Oxidation: Organic peracids are strong oxidizing agents and can oxidize other compounds. For example, peroxyacetic acid (CH3COOOH) can oxidize alcohols to corresponding aldehydes or ketones.
CH3COOOH + R-CH2OH -> CH3COOH + R-CHO

3. Reduction: Peroxides can also undergo reduction reactions. For example, sodium borohydride (NaBH4) can reduce hydrogen peroxide to water.
H2O2 + NaBH4 -> 2H2O + NaBO2

Applications:
- Hydrogen peroxide is commonly used as a disinfectant and bleaching agent.
- Organic peracids are used in the synthesis of various organic compounds.
- Peroxides are used as initiators in polymerization reactions.
- Organic peracids are used in the bleaching of textiles and paper.

In conclusion, the functional groups containing two oxygen atoms are peroxides and organic peracids. These groups exhibit unique reactivity and have applications in various fields such as organic synthesis, disinfection, and bleaching.