You-iggy

Sulfur dioxide

Chemical structure of sulfur dioxide

Sulfur dioxide is an inorganic compound with formula SO2.

Table of contents
  1. 1Names
  2. 2Formulae and structures
  3. 3Properties
  4. 4Constituents
  5. 5Thermodynamic properties
  6. 6Solubility
  7. 7Hazards
  8. 8Preparations
  9. 9Chemical reactions
  10. 10References
  11. 11Related substances
  12. 12Related categories

Names

List of substance names

Nomenclature
Name
Typical name
Sulfur dioxide
Compositional nomenclature
Sulfur dioxide
Additive nomenclature
Dioxidosulfur
Other names
Sulfur(IV) oxide
Sulfurous anhydride

Formulae and structures

List of formulae

Formula name
Formula
Typical formula
SO2
Molecular formula
SO2
Compositional formula
SO2
Structural formula
Chemical structure of sulfur dioxide
Structural formula with no conjugation
Chemical structure of sulfur dioxide with no conjugation
Structural formula with no lone pair
Chemical structure of sulfur dioxide with no lone pair
Structural formula with no conjugation and lone pair
Chemical structure of sulfur dioxide with no conjugation and lone pair
Resonance structures
Resonance structure of sulfur dioxide
Resonance structures with no lone pair
Resonance structure of sulfur dioxide with no lone pair
Lewis structure
Lewis structure of sulfur dioxide
Colored Lewis structure
Colored Lewis structure of sulfur dioxide

Properties

List of substance properties

Item
Value
Name
Sulfur dioxide
Formula
SO2
Appearance
Colorless gas
Odor
Struck match smell
Molar mass
64.06 g/mol
Density
2.811 g/L[1]
Gas
1.620 g/cm3[2]
Liquid, -75.5°C
Melting point
−75.47 °C[1]
−75.45 °C[2]
Boiling point
−10 °C[1]
−10.02 °C[2]

Constituents

Constituent atoms

AtomNameOxidation stateNumber
SSulfur+41
OOxygen−22

Ratio of atoms

AtomAtomic weightNumberAtomic ratioWeight ratio
S32.06133.33%50.05%
O15.999266.67%49.95%
SOAtomic ratio
SOWeight ratio

Thermodynamic properties

Phase transition properties

Item
Value
Enthalpy of fusion
7.40 kJ · mol−1[1]
at −75.47°C
Enthalpy of vaporization
24.94 kJ · mol−1[1][2]
at −10°C
Enthalpy of vaporization at 25°C
22.92 kJ · mol−1[1][2]
Enthalpy of other transition

Standard thermodynamic properties

State
Standard enthalpy
of formation
ΔfH°
kJ · mol−1
Standard Gibbs
energy of
formation
ΔfG°
kJ · mol−1
Standard
molar entropy
S°
J · K−1 · mol−1
Standard molar
heat capacity at
constant pressure
Cp°
J · K−1 · mol−1
Liquid−320.5[3]
Gas−296.830[3]−300.194[3]248.22[3]39.87[3]
Un−ionized aqueous solution−322.980[3]−300.676[3]161.9[3]

Solubility

Qualitative solubility

Reactive
Miscible
Very soluble
Soluble
SO2Cl2Sulfuryl chloride
CH3C6H5NO22-Nitrotoluene
(CH3CO)2OAcetic anhydride
CHCl3[1]Trichloromethane
Slightly soluble
Very slightly soluble
Insoluble

Solubility in acetone (g/100 g)[4]

0°C
207

Solubility in acetic acid (g/100 g)[4]

0°C
96.1

Solubility in formic acid (g/100 g)[4]

0°C
82.1

Solubility in methanol (g/100 g)[4]

0°C7°C12.3°C17.8°C26°C
246149.4109.278.646.4

Solubility in ethanol (g/100 g)[4]

0°C7°C12.3°C18.2°C26°C
1158166.448.832.3

Solubility in sulfuryl chloride (g/100 g)[4]

0°C
32.3

Solubility in water (g/100 g)[1]

0°C5°C10°C15°C20°C25°C30°C35°C40°C
22.8319.3116.2113.5411.289.417.86.475.41

Solubility in water (g/100 g)[4]

0°C5°C10°C15°C20°C25°C30°C40°C
22.8319.3116.2113.5411.299.417.815.41

Solubility in water (g/100 g)[4]

8°C10°C14°C20°C26°C30°C36°C40°C46°C50°C
16.815.41310.48.77.86.55.854.5

Solubility in water (g/100 g)[4]

0°C2°C4°C6°C7°C8°C10°C12°C
23.621.820.118.417.616.815.414.2

Solubility in nitrobenzene (g/100 mL solution)[4]

15°C20°C25°C30°C40°C50°C60°C
31.1426.7422.791913.29.877.86

Solubility in 2-nitrotoluene (g/100 mL solution)[4]

15°C20°C25°C30°C40°C50°C60°C
29.0823.619.2216.0711.858.726.88

Solubility in toluene (g/100 mL solution)[4]

20°C25°C30°C40°C50°C60°C
21.7517.0412.449.367.725.47

Solubility in benzene (g/100 mL solution)[4]

30°C40°C50°C60°C
12.758.296.033.4

Solubility in acetic anhydride (g/100 mL solution)[4]

-5°C0°C5°C10°C15°C20°C25°C30°C
19.614.813.612.211.410.69.99

Solubility curve (g/100 g)

0°C20°C40°C60°C80°C100°CTemperature (°C)050100150200250300Solubility (g/100 g)

Solubility curve (g/100 mL solution)

0°C20°C40°C60°C80°C100°CTemperature (°C)010203040Solubility (g/100 mL solution)

Hazards

GHS label[5]

Physical hazards[5]

Health hazards[5]

Environmental hazards[5]

Preparations

Reaction of nonmetal and nonmetal

The reaction of nonmetal and nonmetal can yield sulfur dioxide.

Reaction of sulfur and oxygen
ΔrG−300.194 kJ/mol
K3.91 × 1052
pK−52.59
Reaction of sulfur and ozone
ΔrG−1227.0 kJ/mol
K9.14 × 10214
pK−214.96

Reaction of salt of weak acid and strong acid

The reaction of salt of weak acid and strong acid can yield sulfur dioxide.

Reaction of salt of volatile acid and nonvolatile acid

The reaction of salt of volatile acid and nonvolatile acid can yield sulfur dioxide.

Reaction of oxoacid and dehydrating acidic oxide

The reaction of oxoacid and dehydrating acidic oxide can yield sulfur dioxide.

Decomposition

Decomposition of thermally decomposable substance can yield sulfur dioxide.

Reaction of inactive metal and oxidizing acid

The reaction of inactive metal and oxidizing acid can yield sulfur dioxide.

Reaction of silver and sulfuric acid
ΔrG−12.86 kJ/mol
K1.79 × 102
pK−2.25

Reaction of reducing nonmetal and oxide

The reaction of reducing nonmetal and oxide can yield sulfur dioxide.

Reaction of hydrogen and sulfur trioxide
ΔrG−163.57 kJ/mol
K4.53 × 1028
pK−28.66
Reaction of carbon and sulfur trioxide
ΔrG−247.25 kJ/mol
K2.07 × 1043
pK−43.32
Reaction of carbon and sulfur trioxide
ΔrG−63.61 kJ/mol
K1.39 × 1011
pK−11.14

Electrolysis

Electrolysis of liquid can yield sulfur dioxide.

Electrolysis of sulfur trioxide
ΔrG147.11 kJ/mol
K0.17 × 10−25
pK25.77
Electrolysis of sulfuric acid
ΔrG389.809 kJ/mol
K0.51 × 10−68
pK68.29
Electrolysis of sulfur trioxide
ΔrG383.9 kJ/mol
K0.55 × 10−67
pK67.26

Comproportionation

The reaction of hydrogen sulfide and sulfur trioxide can yield sulfur dioxide.

Chemical reactions

Reaction with base and water

The reaction of base, sulfur dioxide, and water yields oxoacid salt.

Reaction with basic oxide

The reaction of basic oxide and sulfur dioxide yields oxoacid salt.

Reaction with water

The reaction of sulfur dioxide and water yields sulfurous acid.

Reaction with anion

The reaction of sulfur dioxide and anion yields anion.

Reaction of sulfur dioxide and oxide ion
SO2Sulfur dioxide + O2−Oxide ion
SO32−Sulfurous ion
Reaction of sulfur dioxide and phenolate ion
SO2Sulfur dioxide + C6H5OPhenolate ion
C6H5SO3Benzenesulfonate ion

Reaction with reducing nonmetal

The reaction of reducing nonmetal and sulfur dioxide yields elementary substance/oxide and nonmetal oxide.

Reaction of hydrogen and sulfur dioxide
ΔrG−174.064 kJ/mol
K3.12 × 1030
pK−30.49
Reaction of carbon and sulfur dioxide
ΔrG−94.165 kJ/mol
K3.14 × 1016
pK−16.50
Reaction of carbon and sulfur dioxide
ΔrG25.858 kJ/mol
K0.30 × 10−4
pK4.53

Reaction with active metal and water

The reaction of magnesium, sulfur dioxide, and water yields magnesium sulfite and hydrogen.

Reaction with oxidizing species

The reaction of sulfur dioxide and oxidizing species yields a variety of products.

Reaction of sulfur dioxide and oxygen
ΔrG−147.11 kJ/mol
K5.92 × 1025
pK−25.77

Reaction with reducible species

The reaction of sulfur dioxide and manganese(IV) oxide yields manganese(II) sulfate.

Reaction with reducing species

The reaction of reducing species and sulfur dioxide yields a variety of products.

Reaction of hydrogen sulfide and sulfur dioxide
ΔrG−106.94 kJ/mol
K5.43 × 1018
pK−18.74
Reaction of tin and sulfur dioxide
ΔrG−219.4 kJ/mol
K2.74 × 1038
pK−38.44
Reaction of hydrogen and sulfur dioxide
ΔrG−207.62 kJ/mol
K2.36 × 1036
pK−36.37

Precipitation reaction

When a certain chemical species is present in aqueous solution, it reacts with sulfur dioxide to form a precipitate.

Electrolysis of aqueous solution

Electrolysis of aqueous sulfur dioxide yields a variety of products.

Electrolysis of aqueous sulfur dioxide with water as oxidizing agent
ΔrG163.57 kJ/mol
K0.22 × 10−28
pK28.66
Electrolysis of aqueous sulfur dioxide with water as oxidizing agent
ΔrG84.449 kJ/mol
K0.16 × 10−14
pK14.79
Electrolysis of water
ΔrG474.258 kJ/mol
K0.82 × 10−83
pK83.09
Electrolysis of aqueous sulfur dioxide without water as reactant
ΔrG153.08 kJ/mol
K0.15 × 10−26
pK26.82
Electrolysis of aqueous sulfur dioxide with water as non-redox agent
ΔrG−5.166 kJ/mol
K8.04 × 100
pK−0.91

References

List of references

  1. 1
  2. 2
  3. 3
    Janiel J. Reed (1989)
    The NBS Tables of Chemical Thermodynamic Properties: Selected Values for Inorganic and C1 and C2 Organic Substances in SI Units
    National Institute of Standards and Technology (NIST)

  4. 4
  5. 5