Properties and Structure
- Boiling point of hydrogen peroxide is 150.2°C (302.4°F)
- Forms stable adducts with urea and sodium carbonate
- Can be used as a carrier in some reactions with triphenylphosphine oxide
- Has a nonplanar molecular structure with twisted C symmetry
- Exhibits chiral properties and enantiomerism
- O−O bond is a single bond with high rotational barriers for enantiomers
- Dihedral angle between O–H bonds is approximately 100°
- Molecular structures differ in gaseous and crystalline states due to hydrogen bonding
- Crystals of hydrogen peroxide are tetragonal with space group P422
- Enantiospecific interactions may have led to homochirality in RNA world
- Hydrogen peroxide has higher boiling point and melting point compared to analogues
- Analogues adopt similar skewed structures due to repulsion between lone pairs
- Hydrogen disulfide and diphosphane have weak hydrogen bonding and little chemical similarity
- Hydroxylamine crystallizes more readily due to strong hydrogen bonding
- Hydrogen peroxide exhibits unique properties among analogues

Aqueous solutions
- Forms eutectic mixture with freezing-point depression down to -56°C
- Boiling point of mixture is depressed in relation to pure water and pure hydrogen peroxide
- Density of aqueous solutions varies with concentration
- Most commonly available as solutions in water at 3% and 6% concentrations
- Commercial grades range from 70% to 98% and require special care in storage

Natural occurrence
- Produced by biological processes mediated by enzymes
- Detected in surface water, groundwater, and atmosphere
- Sea water contains 0.5 to 14μg/L of hydrogen peroxide, freshwater contains 1 to 30μg/L
- Concentrations in air vary depending on conditions such as season and altitude
- Assay can be used to measure hydrogen peroxide in biological systems

Production
- Hydrogen peroxide is manufactured using the anthraquinone process.
- The process involves reduction of an anthraquinone to anthrahydroquinone, followed by autoxidation.
- Most commercial processes use compressed air for oxidation.
- Effective recycling of extraction solvents and catalysts is crucial for the economics of the process.
- The net reaction for the anthraquinone-catalyzed process is: anthrahydroquinone + oxygen -> hydrogen peroxide + anthraquinone.
- In the past, hydrogen peroxide was prepared by hydrolysis of ammonium persulfate.
- Ammonium persulfate was obtained through the electrolysis of ammonium bisulfate in sulfuric acid.
- This method is no longer used industrially.
- Small amounts of hydrogen peroxide can be formed through electrolysis, photochemistry, and electric arc.
- A commercially viable route for hydrogen peroxide production involves the reaction of hydrogen with oxygen.
- However, direct processes often result in a dilute solution that is uneconomical for transportation.
- None of these alternative routes have reached industrial-scale synthesis yet.

Reactions
- Hydrogen peroxide is a stronger acid than water. Its pK value is 11.65.
- Hydrogen peroxide disproportionates to form water and oxygen.
- The reaction has a negative enthalpy change and a positive entropy change.
- Decomposition is accelerated by temperature, concentration, and pH.
- Alkaline conditions make hydrogen peroxide unstable.
- Various redox-active ions and compounds catalyze the decomposition.
- In acidic solutions, hydrogen peroxide is a powerful oxidizer.
- It can oxidize sulfite ions to sulfate ions.
- The oxidation potentials of hydrogen peroxide are dependent on the specific oxidizing agent.
- Under alkaline conditions, hydrogen peroxide acts as a reductant.
- It can reduce sodium hypochlorite and potassium permanganate, producing oxygen gas.
- This reduction reaction is a convenient method for preparing oxygen in the laboratory.