Synthesis, Structure, and Luminescent Properties of the New Double Borate K3Eu3B4O12

Abstract

The study established the formation of the new double borate K3Eu3B4O12. The Rietveld refi nement of the crystal structure revealed that K3Eu3B4O12 crystallises in the monoclinic syngony with unit cell parameters a = 10.6727(7) Å, b = 8.9086(6) Å, c = 13.9684(9) Å, b = 110.388(2)° (space group P2/c). K3Eu3B4O12 has a layered structure with [Eu8(BO3)8]∞ sheets which are almost parallel to the ab plane. These sheets are formed by pentagonal EuO7 bipyramids, EuO6 octahedras, and BO3 triangles attached to them through common vertices. Neighbouring layers are interconnected via pentagonal EuO7 bipyramids, BO3 triangles, and potassium cations. The luminescence spectrum demonstrates a noticeable emission band at 611 nm, resulting from the 5D0→7F2 transition of Eu3+ ions.

Keywords

• double borates of potassium and rare-earth elements
• ceramic technology
• rietveld method