  We report the synthesis of the quasi-one-dimensional transition metal
trichalcogenide NbSe3 in the few chain limit, including the realization of
isolated single chains. The chains are encapsulated in protective boron nitride
or carbon nanotube sheaths to prevent oxidation and to facilitate
characterization. Transmission electron microscopy reveals static and dynamic
structural torsional waves not found in bulk NbSe3 crystals. Electronic
structure calculations indicate that charge transfer drives the torsional wave
instability. Very little covalent bonding is found between the chains and the
nanotube sheath, leading to relatively unhindered longitudinal and torsional
dynamics for the encapsulated chains.
