The Quasi-One-Dimensional \(\mathrm{Na}_{2-\delta }\mathrm{Mo}_{6}\mathrm{Se}_{6}\)

In 1971, a new type of superconductor was discovered by R. Chevrel: the octahedral \([A_x\mathrm{Mo}_6X_8]\) clusters, where \(X=\) chalcogens and \(A_x=\) metal interstitial atoms with \(0cuprates had not yet been discovered. Chevrel compounds exhibit unconventional superconducting properties of great interest from a fundamental point of view.