Sulfur Oxide Formula

Let us know about Sulfur Oxide Formula. Sulfur oxide (VI), also known as sulfur trioxide or sulfuric anhydride, is a chemical compound of the formula SO 3.

Sulfur trioxide is produced in a dilute gaseous form, through the oxidation of gases containing sulfur dioxide in a contact sulfuric acid plant.

Until now, however, the only preparation of pure sulfur trioxide from SO-containing gases has been a pilot-scale process involving 3 dilute, cryoscopic condensation.

The general process involves the distillation of oleum. The heat required for oleum distillation is most conveniently supplied by hot contact gas from an associated sulfuric acid plant.

It can be prepared in the laboratory by heating sulfuric acid and collecting the precipitate in a chilled receiver. If the vapor condenses above 27 °C, the gamma form is obtained as a liquid.

Sulfur Oxide Formula

If the steam condenses below 27 °C and in the presence of traces of moisture, a mixture of the three forms is obtained. The 3 forms can be separated by fractional distillation.

Physical and Chemical Properties of Sulfur Oxide

Sulfur trioxide is like white needles that turn to smoke in the air. Inhibitors are often encountered to prevent polymerization (National Center for Biotechnology Information, 2017).

Its molecular weight is 80.066 g/mol, its density is 1.92 g/cm/g/mL and the melting and boiling points are 16.8 ºC and 44.7 ºC, respectively. (Royal Society of Chemistry, 2015).

The compound reacts with water with explosive force, forming sulfuric acid due to its acidity. Sulfur trioxide carbonates organic matter.

Sulfur trioxide absorbs moisture quickly, emitting thick white smoke. A solution of the trioxide in sulfuric acid is called fuming sulfuric acid or oleum. (Sulfur trioxide, 2016).

The reaction of sulfur trioxide and oxygen difluoride is very vigorous and results in an explosion if the reaction is carried out in the absence of a solvent, the reaction of excess sulfur trioxide with tetrafluoroethylene causes explosive decomposition to carbonyl fluoride and sulfur dioxide.

The reaction of anhydrous perchloric acid with sulfur trioxide is violent and is accompanied by the evolution of considerable heat. Sulfur trioxide reacts violently with liquid nitrile chloride, even at 75 °C.

The reaction of sulfur trioxide and lead oxide results in leucorrhoea. The combination of iodine, pyridine, sulfur trioxide and formamide evolved a gas under pressure after several months.

This is due to the slow formation of sulfuric acid, the dehydration of formamide to external water or hydrogen cyanide (SULFUR TRIOXIDE, SF).

Feedback and Hazards

Sulfur trioxide is a stable compound, incompatible with organic matter, finely ground metals, bases, water, cyanides, and a wide variety of other chemicals.

The substance is a strong oxidant and reacts violently with combustible and reducing materials and organic compounds causing fire and explosion hazard.

Reacts violently with water and moist air to produce sulfuric acid. The solution in water is a strong acid, it reacts violently with alkalis and combustible metals to form flammable/explosive gases.

 The compound is corrosive to metals and clothing. Irritation of eyes and skin. Ingestion causes severe burns to the mouth, esophagus and stomach. The vapor is very toxic by inhalation. (National Institute for Occupational Safety and Health, 2015)

In case of eye contact you should check if you are wearing contact lenses and remove them immediately. Eyes should be washed with running water for at least 15 minutes, keeping the eyelids open. You can use cold water. The ointment should not be used for the eyes.

If the chemical comes into contact with clothing, remove it as soon as possible, while protecting your hands and body. Place the victim under the safety shower.

If the chemical gets on the victim’s exposed skin, such as the hands, gently and carefully wash the skin with contaminated water and non-abrasive soap. You can use cold water. If irritation persists, seek medical attention. Wash contaminated clothing before reusing.

In case of inhalation, the victim should be allowed to rest in a well-ventilated area. If inhalation is severe, the victim should be transported to a safe area as soon as possible. Loose clothing such as shirt collars, belts or ties.

If the victim has difficulty breathing, oxygen should be administered. If the victim is not breathing, mouth-to-mouth resuscitation is resumed. Always bear in mind that it can be dangerous for the person providing help to perform mouth-to-mouth resuscitation when the inhaled material is toxic, infectious or corrosive.

In all cases you should seek immediate medical attention (Material Safety Data Sheet Sulfur trioxide, 2013).


Sulfur trioxide is an essential reagent in sulfide reactions. This process provides detergents, dyes and pharmaceuticals. It is produced from sulfuric acid in situ or it is used as a fuming sulfuric acid solution.

Air pollution by sulfur oxides is a major environmental problem, with millions of tons of sulfur dioxide and trioxide being emitted into the atmosphere every year. These compounds are harmful to plant and animal life as well as many building materials.

Another big problem is acid rain. Both sulfur oxides dissolve in atmospheric water droplets to form acid solutions that can be very harmful if distributed as rain.

It is believed that the main reason for the acidity of acid rain is sulfuric acid, which can damage forests and cause fish kills in many lakes.

Acid rain is also acidic to metals, lime and other materials. Potential solutions to this problem are costly due to the difficulty of extracting sulfur from coal and oil prior to combustion.

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