Bi0.5Pb0.5FeO3 with Unusual Pb Charge Disproportionation: Indication of a Systematic Charge Distribution Change in Bi0.5Pb0.5M O3 (M: 3d Transition Metal)

Shiori Kihara; Yuki Sakai; Shogo Wakazaki; Takumi Nishikubo; Takehiro Koike; Ko Mibu; Hongwu Yu; Yoichi Okimoto; Shin-Ya Koshihara; Masaki Azuma

doi:10.1021/acs.inorgchem.2c01911

Bi_0.5Pb_0.5FeO₃ with Unusual Pb Charge Disproportionation: Indication of a Systematic Charge Distribution Change in Bi_0.5Pb_0.5M O₃ (M: 3d Transition Metal)

Inorg Chem. 2022 Aug 15;61(32):12822-12827. doi: 10.1021/acs.inorgchem.2c01911. Epub 2022 Aug 4.

Authors

Shiori Kihara¹, Yuki Sakai^{1

2}, Shogo Wakazaki¹, Takumi Nishikubo^{1

2}, Takehiro Koike¹, Ko Mibu³, Hongwu Yu⁴, Yoichi Okimoto⁴, Shin-Ya Koshihara⁴, Masaki Azuma^{1

2}

Affiliations

¹ Laboratory for Materials and Structures, Tokyo Institute of Technology, Yokohama 226-8503, Japan.
² Kanagawa Institute of Industrial Science and Technology (KISTEC), Ebina 243-0435, Japan.
³ Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
⁴ Department of Chemistry, Tokyo Institute of Technology, Tokyo 152-8551, Japan.

PMID: 35925759
DOI: 10.1021/acs.inorgchem.2c01911

Abstract

Bi_0.5Pb_0.5FeO₃ with 1:1 mixture of Bi and Pb having charge degrees of freedom at the A-site of perovskite oxide ABO₃ is obtained for the first time by high-pressure synthesis. Comprehensive synchrotron X-ray powder diffraction, optical second harmonic generation, Mössbauer spectroscopy, and hard X-ray photoemission spectroscopy measurements revealed that Bi_0.5Pb_0.5FeO₃ is a canted antiferromagnetic insulator crystalizing in a nonpolar tetragonal I4/mcm structure with √2a × √2a × 2a unit cell and has unusually Pb charge disproportionated Bi³⁺_0.5Pb²⁺_0.25Pb⁴⁺_0.25Fe³⁺O₃ charge distribution. The valence of transition metal M in Bi_0.5Pb_0.5MO₃ changes from 3.5+ to 3+ and finally to 2+ from Mn to Fe and to Ni, from left to right in the periodic table as the 3d-level becomes deeper. The valences of Bi and Pb increase to compensate for the decrease in the M's valence, and Pb changes from 6s² (2+) to 6s⁰ (4+) before Bi changes.