Crystal growth of an unusual salt derived from methanesulfonic acid: Rb(CH₃SO₃)(CH₃SO₃H)

Centimeter-sized crystals of a new rubidium methanesulfonic acid salt, (methanesulfonato-κO)(methanesulfonic acid-κO)rubidium(I), [Rb(CH₃SO₃)(CH₃SO₃H)], have been prepared via precipitation from methanesulfonic acid and water under vacuum. The salt crystallizes in the monoclinic space group C2/c (No. 15). The structure is comprised of one-dimensional (1D) chains of alternating edge- and corner-sharing dirubidium cuboctahedra bridged by antiparallel methanesulfonate groups. The 1D chains are tightly packed via hydrogen bonding to adjacent chains with the two methanesulfonate units sharing a single H atom equally between them. The low-dimensional structure has a large optical bandgap of 5.4 eV with an absorption edge of 210 nm.