Quasi-One-Dimensional Structure and Possible Helical Antiferromagnetism of RbMn₆Bi₅

Quasi-one-dimensional materials exhibit not only unique crystal structure but also abundant physical properties such as charge density wave, Luttinger liquid, and superconductivity. Here we report the discovery, structure, and physical properties of a new manganese-based quasi-one-dimensional material RbMn₆Bi₅, which crystallizes in a monoclinic space group C2/m (No. 12) with lattice parameters a = 23.286(5) Å, b = 4.6215(9) Å, c = 13.631(3) Å, and β = 125.00(3)°. The structure features [Mn₆Bi₅]^-1 double-walled column extending along the [010] direction, together with Bi-Bi homoatomic bonds linking the columns and the countercation Rb⁺. The temperature-dependent resistivity clearly indicates a significant resistivity anisotropy for RbMn₆Bi₅, whereas the magnetic susceptibility and specific heat measurements show that RbMn₆Bi₅ is antiferromagnetic below 82 K. The density functional theory calculations indicate that RbMn₆Bi₅ is a quasi-one-dimensional metal with possible helical antiferromagnetic configuration. The discovery of RbMn₆Bi₅ confirms the viability of discovering new quasi-one-dimensional materials in manganese-based compounds.