Isolation of one-dimensional linear atomic carbon chains without bulky end groups is challenging. Now, the transmetallation of linear carbon fragments from Au(I) precursors gives Au|Cn|Au junctions, with the carbon chain directly attached to the electrodes. Chains of 12 or more carbon atoms show bond equalization towards a cumulene ⋯C=C=C=C⋯ valence structure with enhanced charge transport.