Hydrogen iodide, anhydrous

Hydrogen iodide (HI) is a diatomic molecule and hydrogen halide. Aqueous solutions of HI are known as hydroiodic acid or hydriodic acid, a strong acid. Hydrogen iodide and hydroiodic acid are, however, different in that the former is a gas under standard conditions, whereas the other is an aqueous solution of the gas. They are interconvertible. Wikipedia

Data from the Hazardous Materials Table

(3) Hazard Class 2.3 Poisonous gas	(4) Identification number UN 2197	(5) Packing Group n/a
(6) Labels
(7) Special Provisions (§172.102) ×Note: Special provisions may be very complex. The extracts are taken from 49 CFR §172.102. Please be careful with the information, as necessary, additional conditions may be applied that are not written here. Please check the original source and report bugs. 3 This material is poisonous by inhalation (see §171.8 of this subchapter) in Hazard Zone C (see §173.116(a) of this subchapter), and must be described as an inhalation hazard under the provisions of this subchapter. Browse special provision 3 B14 Each bulk packaging, except a tank car or a multi-unit-tank car tank, must be insulated with an insulating material so that the overall thermal conductance at 15.5 °C (60 °F) is no more than 1.5333 kilojoules per hour per square meter per degree Celsius (0.075 Btu per hour per square foot per degree Fahrenheit) temperature differential. Insulating materials must not promote corrosion to steel when wet. Browse special provision B14 N86 UN pressure receptacles made of aluminum alloy are not authorized. Browse special provision N86 N89 When steel UN pressure receptacles are used, only those bearing the “H” mark are authorized. Browse special provision N89
(8) Packing Authorizations (§173.***) (8A) Exceptions None (8B) Non-bulk 304 see 49 CFR §173.304 (8C) Bulk 314, 315 see 49 CFR §173.314, 315
(9) Quantity Limits (9A) Passenger aircraft/rail Forbidden (9B) Cargo aircraft only Forbidden
(10) Vessel stowage (10A) Location D Stowage category “D” means the material must be stowed “on deck only” on a cargo vessel or on a passenger vessel carrying a number of passengers limited to not more than the larger of 25 passengers or one passenger per each 3 m of overall vessel length, but the material is prohibited on a passenger vessel in which the limiting number of passengers is exceeded. Source: 49 CFR §172.101(k) (10B) Other 40 Stow “clear of living quarters”. Source: 49 CFR §176.84