Ba₂B₆O₁₁, a Member of the BaO‐B₂O₃ Family, Featuring a Layer Framework

Abstract

Ba2B6O11, a new member of the BaO‐B2O3 family, has been found and features a layered structure. The single‐crystal X‐ray structural analysis revealed that Ba2B6O11 crystallizes in the monoclinic space group P21/c. The parameters of the monoclinic unit cell are a = 9.115(1), b = 7.773(1), c = 12.696(2) Å, β = 100.325(9)°, and Z = 4. The new centrosymmetric alkaline earth metal borate, Ba2B6O11, is characterized by a 2D B–O framework composed of the basic building block (B6O14) with the Ba2+ cations filling the channels formed by the (B6O14) units or located between the (B6O10)∞ layers. Ba2B6O11 has a short cut‐off edge of 240 nm. Based on a theoretical calculation, it has been proven that Ba2B6O11 has a birefringence of 0.04 and a relatively large indirect band gap of 4.94 eV, which is close to the experimental value of 5.17 eV. Its structure is discussed in terms of the B–O framework and dimensional reduction formalism together with the other structures reported in the BaO‐B2O3 phase diagram.

Application of the Dimensional Reduction Formalism to Pb12[Li2(P2O7)2(P4O13)2](P4O13): a Phosphate Containing Three Types of Isolated P–O Groups

“…Many examples are also observed in metal chalcogenides . Recently, the dimensional reduction formalism has been used to describe the structure conversion of borates in Li 2 O–B 2 O 3 and BaO–B 2 O 3 systems . In this Communication, dimensional reduction is applied to phosphate: we employ Li 2 O as the dimensional reduction agent, incorporating it into a covalent structure, Pb 3 P 4 O 13 , to discover a new phosphate, Pb 12 [Li 2 (P 2 O 7 ) 2 (P 4 O 13 ) 2 ]­(P 4 O 13 ).…”