[Table II] gives the properties of the more important war cases (compiled by Major R. E. Wilson, C. W. S.).

The gases used by the Germans may also be classified by the names of the shell in which they were used. [Table III] gives such a classification.

Markings for American Shell

In selecting markings for American chemical shell, red bands were used to denote persistency, white bands to denote non-persistency and lethal properties, yellow bands to denote smoke, and purple bands to denote incendiary action. The number of bands indicates the relative strength of the property indicated; thus, three red bands denote a gas more persistent than one red band.

The following shell markings were actually used:

1 WhiteDiphenylchloroarsine
2 WhitePhosgene
1 White, 1 redChloropicrin
1 White, 1 red, 1 white75% Chloropicrin, 25% Phosgene
1 White, 1 red, 1 yellow 80% Chloropicrin, 20% Stannic Chloride
1 RedBromoacetone
2 RedBromobenzylcyanide
3 RedMustard Gas
1 YellowWhite Phosphorus
2 YellowTitanium Tetrachloride

TABLE II

Physical Constants of Important War Gases

Name of GasFormula Molecular
Weight
Liquid
Density
at 20° C.
under Own
Pressure
Melting
point,
°C.
Boiling
point,
°C.
Vapor
Pressure
at 20° C.
(mm. Hg)
BromoacetoneC₃H₅BrO136.981.7(?)- 54 1269(?)
Carbon monoxideCO 28.00(Gas)-207 -190(Gas)
Cyanogen bromideBrCN106.022.01 52 61.389
Cyanogen chlorideClCN 61.561.186- 6 15 1002
ChlorineCl₂ 70.921.408-101.5 33.65126
ChloropicrinCl₃C(NO₂)164.391.654- 69.211218.9   
Dichloroethyl sulfide(CH₃CHCl₂)S169.061.27412.5216.06  
Diphenylchloroarsine(C₆H₅)₂AsCl264.561.42244333.0025
Hydrocyanic acidHCN 27.11 .697- 14   26.1603
Phenyldichloroarsine C₆H₅AsCl₂210.96 1.640...253.022
PhosgeneCOCl₂ 98.921.38 ...   8.21215
Stannic chlorideSnCl₄260.542.226- 33 11418.58 
SuperpaliteCCl₃COOCl197.851.65 ...12810.3  
Xylyl bromide( CH₃)C₆H₄CH₂Br 185.031.381- 2  214.5...

TABLE III