Ba2Gd2(Si4O13) contains finite Si4O13 chains and Gd2O12 dimers. It is a representative of a rare class of silicates containing Si4O13 chains.

The title compound, dibarium digadolinium(III) tetra­silicate, crystallized from a molybdate-based flux. It represents a new structure type and contains finite zigzag-shaped C 2-symmetric Si4O13 chains and Gd2O12 dimers built of edge-sharing GdO7 polyhedra. The [9+1]-coordinated Ba atoms are located in voids in the atomic arrangement. All atoms are in general positions except for one O atom, which lies on a twofold axis. The structure is compared with those of the few other known tetra­silicates.