Synthesis, Structure, and Characterization of a Layered Mixed Metal Oxychloride, PbVO₃Cl

Lattice Anharmonicity of Stereochemically Active Lone Pairs Controls Thermochromic Band Gap Reduction of PbVO3Cl

“…The vanadium atom is slightly off-center in the VO 5 square pyramid with a short doubly bonded apical V–O bond (1.599–1.611 Å) and four long bonds of 1.824–1.920 Å and of 1.805–1.956 Å for Pb and Ba, respectively. These results agree with previous structural reports …”

“…Both PbVO 3 Cl and BaVO 3 Cl adopt the orthorhombic Pnma space group, in agreement with previous structural reports. , Results from powder X-ray diffraction analyses of both compounds are provided in Tables S1 and S2. X-ray fluorescence results (Table S3) indicate 1 mol Pb:1 mol V ratio, in agreement with powder XRD.…”

“…Lone pair states and concomitant structural distortions have been previously observed for lead oxides and chalcogenides as a result of the hybridization of unoccupied Pb 6p states with the antibonding states originating from the interaction of Pb 6s states with anion p states (Figure ). , However, in mixed-anion PbVO 3 Cl, in addition to the Pb–O hybridization, the stereoactive lone pair states are also amenable to mixing with Cl states. Based on photoemission measurements, the Cl 3p (∼6 eV) atomic states are higher in the valence band as compared to O 2p (∼9 eV) atomic states.…”

“…This paper establishes the unique effect of thermally induced structural distortions derived from a stereochemically active lone pair on a thermochromic transition in the mixed-anion inorganic compound, PbVO 3 Cl. Previous work on this material was motivated by the Pb 6s 2 lone pairs . Unlike other mixed anion compounds containing lone pairs where the harder cation interacts with the oxide while the softer metal interacts with the softer anion, e.g., chalcogenide or halide, the 6s 2 lone pairs in PbVO 3 Cl simultaneously interact with both O and Cl, and thus PbVO 3 Cl presents a special opportunity to evaluate the structural stability of lone pair interactions with anions of very different electronegativities.…”

Zn3Sb4O6F6 and KI-Doped Zn3Sb4O6F6: A Metal Oxyfluoride System for Photocatalytic Activity, Knoevenagel Condensation, and Bacterial Disinfection

“…Although a variety of inorganic materials exhibit photocatalytic behavior and contribute to dye degradation, − oxyhalide (L–O–X) and metal oxyhalide (M–L–O–X) compounds comprising lone pair elements [M: transition metal ion, L: p block cation with stereochemically active lone pairs, O: oxide atom, and X: halide atom] are among the least investigated photocatalysts (e.g., Bi 2 MO 4 Cl (M = Y/La/Bi), PbBiO 2 X, Bi 12 O 17 Cl 2 , Bi 3 O 4 Cl, Bi 24 O 31 Cl x Br 10– x , PbBiO 2 Br/BiOBr, PbBiO 2 Br/UiO-66-NH 2 , (mpg-C 3 N 4 /PbBiO 2 Br), Bi 4 NbO 8 Cl, Bi 24 O 31 Cl 10 , Sb 4 O 5 Cl 2 , and Sb 4 O 5 Br 2 ,,− ). In general, metal oxychloride (e.g., Bi 4 AO 6 Cl 2 (A = Ba, Sr, and Ca),Cs x (UO 2 )­OCl x ( x ∼ 0.9), PbVO 3 Cl, Ni 5 (TeO 3 ) 4 Cl 2 ), and oxybromide (e.g., REOBr (RE = Tb, Dy, Ho, Er, and Tm)) compounds possess layered structures and the halide atoms (Cl/Br) are present in the van der Waals gap, whereas in metal oxyfluoride compounds, − the fluoride atoms are directly attached with the metal center through covalent bonds and the probable structure variations could be attributed by the size and electronegativity differences of the halide atoms. Among the metal oxyhalides comprising lone pair elements, a few metal oxyfluorides have been reported so far; however, no such reports have been found on photocatalytic activities.…”