The crystal structure of a bimuth–transition metal phosphate Bi6TiP2O16

Crystal structures and polymorphism in compounds Bi6+xT1−xP2O15+y, T=first row transition metals and Pb

“…The experimental conditions for the preparation and crystal growth have been described in detail for Bi 6 TiP 2 O 16 [1], Bi 6 (Mn 0.6 Bi 0.4 )P 2 O 15 [2] and the Fe, Ni and Zn compounds [3] except that the corresponding transition metal oxides were used. The regimen of consecutive refiring and repelletizing is necessary to achieve single phase, or nearly single-phase material.…”

“…The compound Bi 6 TiP 2 O 16 [1] is a new structure type in the complex phase space Bi-Pb-transition metals-phosphates, vanadates and arsenates. Its structure consists of OBi 4 tetrahedra that share edges to form two-dimensional (2-D) Bi 2 O 2 layers that are spanned by PO 4 tetrahedra and TiO 6 octahedra to form a threedimensional (3-D) network.…”

Synthesis and crystal structure of Bi6(Bi0.5Cu0.5)V2O15+

“…The preliminary experiments of suitable crystals, in the single crystal X-ray diffractometer resulted in a monoclinic crystal system with the lattice parameters a ¼14.8931(24) Å, b¼5.4701(4) Å, c¼11.1117 Table 1) in order to adopt the previous convention [13,14]. The positions of the bismuth Bi1, Bi2 and Bi3 atoms located using direct methods (using HKLF4) coincided with that of the earlier positional coordinates and were refined (using HKLF5) which results in the change in R factor from 67.72% to 19.96% with the difference peak/deepest hole changing from 69.722/ À 30.025 to 34.794/ À 20.492.…”

“…Many of these structures can be viewed as consisting of (OBi) 4 or (OBiM) 4 (M ¼metal ion) tetrahedral units leading to layers or chains that are connected by XO 4 (X ¼P, V, As) groups [1]. The identification of Bi 6 TiP 2 O 16 [13] and its structural polymorphs synthesized using other first row transition metal ions Bi 6 þ x M 1 À x P 2 O 15 þ y (M ¼Cr, Mn, Fe, Co, Ni, Cu, Zn and Pb) [14][15][16] contain the two-dimensional Bi 2 O 2 layers that are found typically in the Aurivillius phases (e.g. Bi 4 V 2 O 11 and its reduced product Bi 4 V 2 O 10.66 ).…”

“…The synthesis, characterization of structure and other physical properties of new bismuth, vanadium and other transition metal ions containing oxides is highly relevant considering the highest oxide ion conductivity known in Bi 4 V 2 O 11 [3] and its various metal ions substituted products along with other established bismuth based photocatalysts such as BiVO 4 [17] and Bi 2 WO 6 [18]. Our continued exploration of bismuth containing oxides for applications related to photocatalysis and oxide ion conductivity [19,20] resulted in Bi 6.5 Cu 0.5 V 2 O 15 þ y with a structure identified for polymorph A possessed by Bi 6 þ x M 1 À x P 2 O 15 þ y (M¼ Ti, Mn, Fe and Ni) phases [13][14][15]. Herein we describe the synthesis of Bi 6 þ x M 0.5 V 2 O 15 þ y (M ¼Mn, Co, Ni, Cu, Zn) and the detailed structural characterization of Bi 6.5 Cu 0.5 V 2 O 15.2 .…”