A New Fluoroborate Ba5Eu3(BO3)6F: Crystal Structure and Luminescence Properties

The barium europium fluoroborate, Ba 5 Eu 3 (BO 3 ) 6 F, was synthesized using a high-temperature solution method. This compound crystallizes in the monoclinic space group P 2 1 / c (no.14) with unit cell parameters a = 13.6967(2) Å, b = 8.7104(2) Å, c = 7.64540(10) Å, β = 99.0320(10)°, V = 900.82(3) Å 3 , and Z = 2. It is isostructural to the known fluoroborate Ba 5 Gd 3 (BO 3 ) 6 F. Its three-dimensional structure consists of edge-sharing Ba and Eu distorted polyhedra. The luminescent properties of Ba 5 Eu 3 (BO 3 ) 6 F were investigated. The photoluminescence emission spectrum of Ba 5 Eu 3 (BO 3 ) 6 F is dominated by the Eu 3+ 5 D 0 → 7 F 2 transition, consistent with the observed intense red luminescence. The high intensity of the 5 D 0 → 7 F 2 emission further indicates that Eu 3+ ions occupy low-symmetry crystallographic sites. Single crystals of a new barium europium fluoroborate were grown out of a molten flux. The 3D framework consists of edge-shared Ba and Eu distorted polyhedra with isolated BO3 and BO4 units. The material luminesces red