Acetylene Ethyne 57113-74-3 25067-58-7 74-86-2 Welding Gas C01548 ethenylene c0526 Azetylen C2H2 CH#CH CHEBI:27518 Acetylen Acetylene, dissolved [UN1001] [Flammable gas] EINECS 200-816-9 Ethine HSDB 166 Narcylen UN1001 Carbon (C2) Dicarbon Ethin HC#CH ETD ETHENYLENE GROUP [CH(CH)] vinylene Ethyne, homopolymer Polyacetylene