Synthesis and crystal structure of a new strontium borate, Sr2B16O26

The crystal structure of Sr2B16O26 consists of a 3D network of the complex borate anion [B16O32]16−, formed by 12 BO3 triangles and 4 BO4 tetrahedra, which can be viewed as three linked [B3O7]5− triborate groups bonded to one pentaborate [B5O10]5− group and two BO3 triangles; this leads to a Fundamental Building Block (FBB) with the shorthand notation 16: ∞3[3 × (3:2Δ + T) + (5:4Δ + T) + 2Δ].