polyyne

thumb|right|Diacetylene, the simplest polyyne

A polyyne is any organic compound with alternating single and triple bonds; that is, a series of consecutive alkynes, {{chem2|(\sC\tC\s)_{n} }} with n greater than 1. These compounds are also called polyacetylenes, especially in the natural products and chemical ecology literature, even though this nomenclature more properly refers to acetylene polymers composed of alternating single and double bonds (which are polyenes) {{chem2|(\sCR\dCR′\s)_{n} }} with n greater than 1. They are also sometimes referred to as oligoynes, or carbinoids after "carbyne" {{chem2|(\sC\tC\s)_{∞}|}}, the hypothetical allotrope of carbon that would be the ultimate member of the series. The synthesis of this substance has been claimed several times since the 1960s, but those reports have been disputed. Indeed, the substances identified as short chains of "carbyne" in many early organic synthesis attempts would be called polyynes today.