Synthesis and Characterization of a New Sillenite Compound—Bi₁₂(B_0.5P_0.5)O₂₀

Abstract

A new sillenite compound, Bi 12 (B 0.5 P 0.5 )O 20 , was synthesized using a solid-state reaction method. The stoichiometry was confirmed by XRD analyses, microstructural investigations, and quantitative elemental analysis. An investigation of the dielectric properties at frequencies from 100 Hz to 1 MHz revealed a broad, highly frequency-dispersive, relaxor-like dielectric anomaly, which appeared in the temperature range of ؊80°-100°C. The permittivity, Q ؋ f value, and temperature coefficient of the resonant frequency, measured at ϳ5.5 GHz, were determined to be 37.4, 850 GHz, and ؊19 ppm/K, respectively.

Dielectric Characteristics of Bismuth Oxide Solid Solutions with a Fluorite‐Like Crystal Structure

“…11,12 We have characterized the dielectric properties of several sillenite ceramics and have indicated their potential application for passive electronic components. 13,14 We have found the same also is true for a tetragonal Bi 3 NbO 7 . 15 Despite the encouraging dielectric properties, the most important feature of Bi 2 O 3 and its solid solutions for the modern passive-component industry is the fact that, although they are very reactive, they do not react with silver (or Ag 2 O).…”

“…Several phases in the systems with WO 3 and MoO 3 crystallize as supercells of the fluorite structure. These supercells are mainly tetragonal solid solutions with representatives such as Bi 14 3,31 The overview of the Bi 2 O 3 -rich corners of the binary systems ( Fig. 1) shows that the stabilities of fluorite-like phases correlate with the ionic radii and charges of the dopant ions.…”

A Stoichiometric Model for Sillenites

“…Several M 4+ analogues with comprehensively studied compositions include Bi 12 SiO 20 , 31 Bi 12 TiO 20 , 32,33 Bi 12 GeO 20 , 8 Bi 12 -MnO 20 , 34 and Bi 12 (B 0.5 P 0.5 )O 20 . 35 Even M 4+ sillenites with vacancies at the tetrahedral site can be, according to the model proposed, considered as stoichiometric as long as the oxygen sublattice is fully occupied. An example of such a sillenite is Bi 12 (Fe 0.35 P 0.59 0 0.06 )O 20 .…”

Electron diffraction study of the sillenites Bi12SiO20, Bi25FeO39 and Bi25InO39: Evidence of short-range ordering of oxygen-vacancies in the trivalent sillenites

“…The sillenite structure is exclusive to bismuth oxygen compounds and is described by the meta-stable parent-compound γ -Bi 2 O 3 which houses the Bi 3+ ion in the center of the tetrahedron. 33 In the sillenites, Bi 12 SiO 20 and Bi 12 GeO 20 , the sillenite structure is stabilized by fully replacing the Bi 3+ ion by small tetravalent ions. These two tetravalent sillenites have the simplest structure of all sillenites and their structure will be referred to as the ideal structure.…”

“…11,12 The last decade has witnessed an increase in the study of these compounds for photocatalysis and novel applications. [13][14][15][16][17] The physical and electronic structure of sillenites remains important and continues to motivate synthesis, [18][19][20][21][22] optical, [23][24][25] first principles, [26][27][28] dielectric, 29 magnetism, 30 and high-pressure studies. 31,32 Figure 1 shows a representative sillenite structure.…”