New structure type. Layered phosphate-carbonate mineral.
The layers are built of disordered edge-sharing MnO6 octahedra. Each fourth Mn site in octahedral layer is vacant leading to an ordered system of hexagonal "holes" that contain the carbonate groups, thus leading to the following layer composition: [Mn3O8(CO3)]. The Mn-CO3 layers are joined by the phosphate tetrahedra and Na-bearing polyhedra.