linguistic:voice_change, structural:expansion
Addition of halogens and related reagents

Alkynes characteristically are capable of adding two equivalents of halogens and hydrogen halides.

The addition of nonpolar E−H bonds across C≡C is general for silanes, boranes, and related hydrides. The hydroboration of alkynes gives vinylic boranes which oxidize to the corresponding aldehyde or ketone. In the thiol-yne reaction the substrate is a thiol.

Addition of hydrogen halides has long been of interest. In the presence of mercuric chloride as a catalyst, acetylene and hydrogen chloride react to give vinyl chloride. While this method has been abandoned in the West, it remains the main production method in China.