Synthesis, Structural Characterization, and Cation Transport of Tripotassium Pentabismuth Arsenate K₃Bi₅(AsO₄)₆

Abstract

During the exploration of the K 2 O-Bi 2 O 3 -As 2 O 5 system, single crystals of a new arsenate of trivalent bismuth, K 3 Bi 5 (AsO 4 ) 6 , were isolated by solid state reaction at 600 • C. The title compound crystallizes in the monoclinic system, space group C2/c (N • 15) with a = 18.257(2)Å, b = 7.260(1)Å, c = 20.130(4)Å, β = 119.86(1) • , and Z = 4. Its structure consists of a three-dimensional framework made up of AsO 4 tetrahedra and BiO 6 and BiO 7 polyhedra sharing edges and corners, delimiting cavities wherein K + ions reside. This compound exhibits a potassium ion conductivity but with rather low conductivity value.

Synthesis, Single‐Crystal Structure, Dielectric Properties of a New Phosphate K3Bi6.5(PO4)7.5

“…[6] This activity seems accentuated in the case of Bi(3), since the oxygen atom O(17) of its environment is located at a distance of 2.10 Å, the bond is relatively short compared to those found usually in the bibliography. [14,16,17] The phosphorus tetrahedra are connected to the bismuth polyhedra by corners (Figure 5 and 6) and form a three-dimensional anionic framework [Bi 6.5 (PO 4 ) 7.5 ] 3-. The potassium atoms are located in tunnel the [101] direction.…”

“…[10] Bi-based materials are well known in the photocatalytic system. [11] In previous papers, we have investigated the ternaries systems A + 2 O-Bi 2 O 3 -P 2 O 5 and A + 2 O-Bi 2 O 3 -As 2 O 5 (A = Li + , Na + , K + ), and we have synthesized same new materials as single crystal such as Na 3 Bi 2 (AsO 4 ) 3 , [12] K 0.405 Bi 0.865 (AsO 4 ), [13] K 3 Bi 5 (AsO 4 ) 6 , [14] K 6 Bi 2 (P 2 O 7 ) 3 , [15] K 3 Bi 2 (AsO 4 ) 3 , [16] Rb 6 Bi 4 (PO 4 ) 2 (P 2 O 7 ) 3 , [17] K 3 Bi 2 (PO 4 ) 3 , [18] and Na 5 Bi 2 (AsO 4 )(As 2 O 7 ) 2 . [19] The structural diversity of this ternary system and the obtaining of novel crystal structures motivates us to continue research.…”