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Oxides and peroxides

Sulfur dioxide

Also known as sulphur dioxide, Sulfurous anhydride, Sulfurous oxide

CAS 7446-09-5Formula O2SMolar mass 64.07 g/molEC 231-195-2
GHS signal word: Danger. Pictograms: Gas under pressure, Corrosive, Acute toxicity (severe), Serious health hazard 96 suppliers listed
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Sulfur dioxide chemical structure, O2S, CAS 7446-09-5
2D chemical structure

Key facts

What buyers check first

All properties
Appearance
Colorless gas or liquid
Melting point
-75.5 °C
Boiling point
-10.1 °C
Density
Relative density (water = 1): 1.4 (liquid, -10 °C)
Solubility
In water, 1.07 × 10⁺⁵ mg/L at 21 °C
HS code
281129
Category
Oxides and peroxides
UN number
UN 1079
Illustrative photo, a small gas cylinder with a regulator in a lab on a laboratory bench
Typical packagingIllustrative packaging image, not the actual product

What is Sulfur dioxide?

Plain description, key identifiers and synonyms

Sulfur dioxide is a sulfur oxide. It has a role as an Escherichia coli metabolite, a food bleaching agent and a refrigerant.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
sulfur dioxide
CAS number
7446-09-5 CAS number cross-checkedOther or deprecated CAS: 12143-17-8, 67015-63-8
EC number
231-195-2
Molecular formula
O2S
UNII
0UZA3422Q4
InChIKey
RAHZWNYVWXNFOC-UHFFFAOYSA-N
InChI
InChI=1S/O2S/c1-3-2
SMILES (canonical and isomeric)
O=S=O

Synonyms

  • sulphur dioxide
  • Sulfurous anhydride
  • Sulfurous oxide
  • Fermenicide liquid
  • Sulfurous acid anhydride
  • Sulfur superoxide
  • Fermenicide powder
  • Sulfur oxide (SO2)
  • Schwefeldioxid
  • Siarki dwutlenek
  • Sulfur dioxide (SO2)
  • Schwefeldioxyd
  • Sulfuroxide
  • INS NO.220
  • (oxo-lambda4-sulfanylidene)oxidane
  • dioxidosulfur
  • Oxosulfane oxide
  • Surfur dioxide (anhydrous)
  • Sulfur dioxide (NF)
  • Sulfur-dioxide
  • UN 1079
  • Sulfur dioxide (SO2) 10% by volume or more SO2
  • Sulfur dioxide, >=99.9%
  • Sulfurdioxide
  • sulfonyl
Show all 35 synonyms
  • sulfuryl
  • sulphonyl
  • sulfer dioxide
  • Dioxide, Sulfur
  • Fermenticide liquid
  • Oxosulfane oxide #
  • Schwefel(IV)-oxid
  • Anhydride, Sulfurous
  • Sulfur dioxide [UN1079] [Poison gas]
  • Dioxo-lambda~4~-sulfane

Physical and chemical properties

Measured values and descriptors computed from the structure

Physical and chemical properties

Measured values, check the supplier specification for your grade

Appearance
Colorless gas or liquidexp.
Odour
Strong suffocating odorexp.
Taste
Acid tasteexp.
Melting point
-75.5 °Cexp.
Boiling point
-10.1 °Cexp.
Density
Relative density (water = 1): 1.4 (liquid, -10 °C)exp.
Autoignition temperature
Not flammableexp.
Solubility
In water, 1.07 × 10⁺⁵ mg/L at 21 °Cexp.
Vapour pressure
Vapor pressure (kPa): 230 at 10 °C, 330 at 20 °C, 462 at 30 °C, 630 at 40 °Cexp.

Values vary by grade. Ask suppliers for the COA or TDS of the batch you buy.

Computed descriptors

Calculated from the structure, useful for screening and formulation

Molecular weight
64.07 g/molcalc.
Exact mass
63.9619 Dacalc.
LogP (octanol/water)
-0.67calc.
Topological polar surface area
34.14 Ųcalc.
Hydrogen bond donors
0calc.
Hydrogen bond acceptors
2calc.
Rotatable bonds
0calc.
Heavy atoms
3calc.
Rings
0calc.
Aromatic rings
0calc.
Fraction sp3 carbons
0calc.
Formal charge
0calc.
Stereocentres
0calc.

Calculated for screening. Confirm critical figures with the supplier.

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Danger
GHS04: Gas under pressure
Gas under pressure
GHS05: Corrosive
Corrosive
GHS06: Acute toxicity (severe)
Acute toxicity (severe)
GHS08: Serious health hazard
Serious health hazard
030NFPA 704 rating

Hazard statements

  • H314Causes severe skin burns and eye damage.
  • H331Toxic if inhaled.
  • H370Causes damage to organs.
Precautionary statements (17)
  • P260Do not breathe dust, fume, gas, mist, vapours or spray.
  • P261Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P264Wash skin thoroughly after handling.
  • P270Do not eat, drink or smoke when using this product.
  • P271Use only outdoors or in a well-ventilated area.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P301 + P330 + P331If swallowed: Rinse mouth. Do not induce vomiting.
  • P302 + P361 + P354If on skin: Take off immediately all contaminated clothing. Immediately rinse with water for several minutes.
  • P304 + P340If inhaled: Remove person to fresh air and keep comfortable for breathing.
  • P305 + P354 + P338If in eyes: Immediately rinse with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
  • P308 + P316If exposed or concerned: Get emergency medical help immediately.
  • P316Get emergency medical help immediately.
  • P321Specific treatment (see supplemental first aid instructions on the label).
  • P363Wash contaminated clothing before reuse.
  • P403 + P233Store in a well-ventilated place. Keep container tightly closed.
  • P405Store locked up.
  • P501Dispose of contents and container in accordance with local regulations.
UN number
UN 1079
Transport hazard class
2.3

GHS classification summary, not a safety data sheet (SDS). Classifications can differ by supplier, grade and concentration. Always check the supplier's SDS.

Full safety data and first aid

Sulfur dioxide suppliers

Sponsored listings first, then the documented ranking: membership, verification, replies, completeness, freshness and ratings

All 96 suppliers
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Where suppliers are based

96 suppliers in 28 countries

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Sulfur dioxide price

Indicative price range per kg from live supplier offers

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Uses and applications

What the substance is used for, by industry and function

Sulfur dioxide is used as a fungicide and preservative postharvest for grapes. (From table).

Sulfur dioxide is ... used to manufacture hydrosulfites, to bleach wood pulp and paper, to process, disinfect, and bleach food, for waste and water treatment, in metal and ore refining, and in oil refining.

Chemicals (H2SO4, salt cake, sulfites, hydrosulfites of potassium and sodium, thiosulfates, alum from shale, recovery of volatile substances), sulfite paper pulp, ore and metal refining, soybean protein, intermediates, solvent extraction of lubricating oils, bleaching agent for oils and starch, sulfonation of oils, disinfecting and fumigating, food additive (inhibition of browning, of enzyme-catalyzed reactions, bacterial growth), reducing agent, antioxidant.

Use classes: Inorganic substances, Food additives.

Pharmacological actions

  • Air Pollutants

Roles

  • Escherichia coli metabolite
  • additive
  • bacterial metabolite
  • bleaching agent
  • food additive
  • food bleaching agent
  • food component
  • metabolite
  • physiological role
  • prokaryotic metabolite
  • reagent
  • refrigerant

Functional uses

  • Antioxidant
  • Biocide
  • Dye
  • Flavouring and nutrient
  • Fragrance

How it is made

(1) By roasting pyrites in special furnaces. The gas is readily liquefied by cooling with ice and salt or at a pressure of three atmospheres. (2) By purifying and compressing sulfur dioxide gas from smelting operations. (3) By burning sulfur.

Produced commercially from the following raw materials: elemental sulfur, pyrites, sulfide ores of non-ferrous metals, waste sulfuric acid and sulfates, gypsum and anhydrite, hydrogen sulfide-containing waste gases, and flue gases from the combustion of sulfurous fossil fuels.

Read more

It is most commonly produced by burning sulfur but can also be produced by burning pyrites in a special furnace or by purifying and compressing sulfur dioxide gas from smelting operations.

Produced by burning molten sulfur in a special burner with a controlled amount of air. The burner gas, free of dust and cooled, is dissolved in water in a series of two towers. In a third tower, the solution is sprayed at the top and flows down while steam is injected at the base. The gas issuing from the third tower is then cooled to remove most moisture and passed up a fourth tower against a countercurrent of sulfuric acid. The dried gas is liquefied by compression

Regulatory status

Inventories, regulations and trade controls that list this substance

Europe

  • EU harmonised classification (CLP Annex VI)
    Index no: 016-011-00-9

Health and food

  • Food additive

United States

  • TSCA inventory (USA)
    Status: Active in US commerce

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code Sulfur dioxide is traded under.

HS 2811.29Indicative HS code

Inorganic oxygen compounds of non-metals, not elsewhere classified in subheading 2811.2

World exports in 2024
$580M
−11.6% vs 2023, imports $596M
2019 to 2024
Top exporters
  1. China21.4%
  2. Germany18.2%
  3. Poland17.5%
Top importers
  1. Germany14.9%
  2. United States13.6%
  3. France * partner reported9.2%

* Partner reported figures, a lower bound.

Reported customs values in USD, not prices.Full trade data

The HS code shown for Sulfur dioxide is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

Quick answers about Sulfur dioxide, based on the data on this page

What is Sulfur dioxide?

Sulfur dioxide is a sulfur oxide. It has a role as an Escherichia coli metabolite, a food bleaching agent and a refrigerant.

What is the CAS number of Sulfur dioxide?

The CAS registry number of Sulfur dioxide is 7446-09-5. Other or deprecated CAS numbers: 12143-17-8, 67015-63-8.

What is the molecular formula and weight of Sulfur dioxide?

The molecular formula of Sulfur dioxide is O2S and its molar mass is 64.07 g/mol.

What is Sulfur dioxide used for?

Sulfur dioxide is used as a fungicide and preservative postharvest for grapes. (From table). Sulfur dioxide is ... used to manufacture hydrosulfites, to bleach wood pulp and paper, to process, disinfect, and bleach food, for waste and water treatment, in metal and ore refining, and in oil refining.

Is Sulfur dioxide hazardous?

Sulfur dioxide carries the GHS signal word "Danger". Main hazards: causes severe skin burns and eye damage, toxic if inhaled, causes damage to organs. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of Sulfur dioxide?

Sulfur dioxide is usually classified under HS code 281129 (II. INORGANIC ACIDS AND INORGANIC OXYGEN COMPOUNDS OF NON-METALS, other). This is indicative, confirm it with your customs broker before shipping.

Where can I buy Sulfur dioxide?

CompoundList lists 96 suppliers of Sulfur dioxide in United States, China, India, Germany and 24 more. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

Where can I buy Sulfur dioxide in India?

14 suppliers in India list Sulfur dioxide on CompoundList. Filter the suppliers list by country and send a request to compare prices, grades and delivery times.

What is the price of Sulfur dioxide?

Suppliers quote Sulfur dioxide on request because prices depend on grade, purity, quantity and destination. A free request on CompoundList gets you several quotes to compare.

Guides for buyers

Practical guides that help when you source, ship or handle Sulfur dioxide

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Data last updated 7 Oct 2026. Details may have changed, please confirm them with the supplier. Report an error on this page
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