Molecule

Critical Diameter (Å)

Molecule

Critical Diameter (Å)

Helium

2.0

Propylene

5.0

Hydrogen

2.4

Ethyl mercaptan

5.1

Acetylene

2.4

1-Butene

5.1

Oxygen

2.8

trans-2-Butene

5.1

Carbon monoxide

2.8

1,3-Butadiene

5.2

Carbon dioxide

2.8

Chlorodi fluoromethane

5.3

Nitrogen

3.0

Thiophene

5.3

Water

3.2

Isobutane to isodocosane

5.6

Ammonia

3.6

Cyclohexane

6.1

Hydrogen sulfide

3.6

Benzene

6.7

Argon

3.8

Toluene

6.7

Methane

4.0

p-Xylene

6.7

Ethylene

4.2

Carbon tetrachloride

6.9

Ethylene oxide

4.2

Chloroform

6.9

Ethane

4.4

Neopentane

6.9

Methanol

4.4

m-Xylene

7.1

Methyl mercaptan

4.5

o-Xylene

7.4

Propane

4.9

Triethylamine

8.4

n-Butane to n-docosane

4.9