β-BaGa[B4O8(OH)](H2O) and Ba4Ga[B10O18(OH)5](H2O): new barium galloborates featuring unusual [B4O8(OH)]5− and [B10O18(OH)5]11− clusters

Centrosymmetric β-BaGa[B₄O₈(OH)](H₂O) with a layered structure and polar Ba₄Ga[B₁₀O₁₈(OH)₅](H₂O) with a novel 3D framework structure have been reported.