The local environment of cations in Bi12.5Er1.5ReO24.5

Polymorphism and Visible-Light-Driven Photocatalysis of Doped Bi2O3:M (M = S, Se, and Re)

“…The substitution of Bi 12.5 Ln 1.5 ReO 24.5 with lanthanides of lower ionic radii results in a decrease of the unit cell length “ a f ” in accordance with the lanthanoid contraction (Figure ). ,− The incorporation of the dopants into the δ-Bi 2 O 3 -type lattice of the compounds 1c – 5c is confirmed by IR- and Raman spectroscopy (Figures and ). In the IR spectra, cubic Bi 14 O 20 (SO 4 ) ( 1c ) and Bi 14 O 20 (SeO 4 ) ( 2c ) show characteristic vibration bands for the corresponding chalcogenate groups ([SO 4 ] 2– : 1057 cm –1 (ν 3 ), 962 cm –1 (ν 1 ), and 599 cm –1 (ν 4 ); , [SeO 4 ] 2– : 836 cm –1 (ν 1 )).…”

“…The cubic compound Bi 14 O 20 (ReO 4.5 ) ( 3c ) with an oxygen-defective fluorite -type structure represents a rare-earth-free compound of the previously reported Bi 12.5 Ln 1.5 ReO 24.5 (Figure ). ,− The unit cell length of Bi 14 O 20 (ReO 4.5 ) ( 3c ) with a f = 5.6469(3) Å is very close to that of Bi 12.5 La 1.5 ReO 24.5 with a f = 5.6456(3) Å because of the similar ionic radii of Bi 3+ ( r ion = 1.03 Å, CN = 6) and La 3+ ( r ion = 1.032 Å, CN = 6) . The substitution of Bi 12.5 Ln 1.5 ReO 24.5 with lanthanides of lower ionic radii results in a decrease of the unit cell length “ a f ” in accordance with the lanthanoid contraction (Figure ).…”

“…Correlation between the ionic radius “ r ion ” of Ln 3+ (Ln = La, Pr, Nd, Sm, Gd, Dy, Ho, and Lu; CN = 6) and the cell parameter “ a f ” in cubic Bi 12.5 LnO 20 (ReO 4.5 ) ,− in comparison to Bi 14 O 20 (ReO 4.5 ) ( 3c ). Based on a diagram with permission from reference (Copyright 2014 Elsevier) and reference (Copyright 2012 Elsevier).…”

“…99,102 Among them, Bi 14 WO 24 is the only ternary example, for which a cubic modification was additionally reported. 103,104 In the case of compounds related to Bi 14 ReO 24.5 , the cubic δphase is reported for quaternary compounds with the composition Bi 12.5 Ln 1.5 ReO 24.5 (Ln = Y, 12,105 La, 12,105,106 Pr, 106 Nd, 12,105 Sm, 107 Eu, 12 Gd, 108 Dy, 109 Ho, 110 Er, 12,111,112 Yb, 113 and Lu 112,114,115 ). Semi and nonmetalstabilized δ-Bi 2 O 3 is only known for the binary systems of Bi 2 O 3 −B 2 O 3 14 and Bi 2 O 3 −BiPO 4 , respectively.…”

Dopant Clusterization and Oxygen Coordination in Ta-Doped Bismuth Oxide: A Structural and Computational Insight into the Mechanism of Anion Conduction

“…Local structure investigation techniques have recently proved to be very suited to obtain the structural information necessary for understanding of the anionic conduction mechanisms on a number of ceramic electrolytes. ,, The local coordination of Bi in undoped δ-Bi 2 O 3 was investigated in early high-temperature extended X-ray absorption fine structure (EXAFS) studies that confirmed the displacement of oxygen from the tetrahedral sites of the fcc cation network, put forth by neutron diffraction investigations. , On the contrary, very few EXAFS studies were addressed to the local atomic structure of Bi-, Y-, Er-, and Yb-doped Bi 2 O 3 , and higher-valent dopants (Re 7+ and Mo 6+ ) were investigated even more infrequently. − In general, the existing evidence of the local atomic structure in doped Bi 2 O 3 is limited and eventually inconclusive, also due to the lack of rigorous constraints in the data analysis.…”