Contrasting Lone-Pair Stereochemistry in Sb³⁺ and Bi³⁺ Chalcogenides: Implications for Structure and Phonon Transport
Abstract
The unique physicochemical properties of chalcogenides containing post-transition metals are often governed by the stereochemical activity of their ns² lone pairs. A comparative structural analysis of bournonite (CuPbSbS₃) and aikinite (CuPbBiS₃) reveals that CuPbSbS₃ has a larger unit cell volume (V = 552.58 ų) than CuPbBiS₃ (V = 534.42 ų), despite antimony (Sb³⁺) being smaller than bismuth (Bi³⁺). This counterintuitive trend originates from the stronger lone pair effect of Sb³⁺, which induces a larger static distortion, leading to a tetrahedral SbS3L (L-lone pair) coordination, while Bi³⁺ exhibits a less asymmetric distortion corresponding to the more compact square-pyramidal BiS5 (or octahedral BiS5L) coordination. These structural differences are corroborated by temperature-dependent Raman spectroscopy, which captures distinct vibrational behaviors reflective of differing lattice dynamics. CuPbSbS₃ exhibits higher anharmonicity, as quantified by anharmonicity coefficients extracted from Raman data. Electron localization function analysis and crystal orbital Hamilton population further confirm the higher activity of the Sb³⁺ lone pair compared to Bi³⁺. Interestingly, despite the lower atomic mass of Sb relative to Bi, both compounds exhibit nearly identical acoustic-phonon cutoff frequencies. Consequently, both CuPbSbS₃ and CuPbBiS₃ display partially suppressed Umklapp scattering and comparable low lattice thermal conductivities at high temperatures, despite their compositional and structural differences.
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BibTeX
@article{tiadi2026contrasting,
title = {{Contrasting Lone-Pair Stereochemistry in Sb³⁺ and Bi³⁺ Chalcogenides: Implications for Structure and Phonon Transport}},
author = {Minati Tiadi and Animesh Bhui and Mohammad Ubaid and Pierric Lemoine and Carmelo Prestipino and Bernard Raveau and Gaelle Riou and Lei Wu and Bin Zhang and Xiaoyuan Zhou and Christophe Candolfi and Priyanshu Sharma and Koushik Pal and Prithwija Mandal and Ajay Soni and Adèle Renaud and Emmanuel Guilmeau},
journal = {Chemistry of Materials},
year = {2026},
month = sep,
doi = {10.1021/acs.chemmater.6c00417},
url = {https://hal.science/hal-05605735v1},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - Contrasting Lone-Pair Stereochemistry in Sb³⁺ and Bi³⁺ Chalcogenides: Implications for Structure and Phonon Transport
AU - Minati Tiadi
AU - Animesh Bhui
AU - Mohammad Ubaid
AU - Pierric Lemoine
AU - Carmelo Prestipino
AU - Bernard Raveau
AU - Gaelle Riou
AU - Lei Wu
AU - Bin Zhang
AU - Xiaoyuan Zhou
AU - Christophe Candolfi
AU - Priyanshu Sharma
AU - Koushik Pal
AU - Prithwija Mandal
AU - Ajay Soni
AU - Adèle Renaud
AU - Emmanuel Guilmeau
PY - 2026
DA - 2026/09/17
JO - Chemistry of Materials
DO - 10.1021/acs.chemmater.6c00417
UR - https://hal.science/hal-05605735v1
AB - The unique physicochemical properties of chalcogenides containing post-transition metals are often governed by the stereochemical activity of their ns² lone pairs. A comparative structural analysis of bournonite (CuPbSbS₃) and aikinite (CuPbBiS₃) reveals that CuPbSbS₃ has a larger unit cell volume (V = 552.58 ų) than CuPbBiS₃ (V = 534.42 ų), despite antimony (Sb³⁺) being smaller than bismuth (Bi³⁺). This counterintuitive trend originates from the stronger lone pair effect of Sb³⁺, which induces a larger static distortion, leading to a tetrahedral SbS3L (L-lone pair) coordination, while Bi³⁺ exhibits a less asymmetric distortion corresponding to the more compact square-pyramidal BiS5 (or octahedral BiS5L) coordination. These structural differences are corroborated by temperature-dependent Raman spectroscopy, which captures distinct vibrational behaviors reflective of differing lattice dynamics. CuPbSbS₃ exhibits higher anharmonicity, as quantified by anharmonicity coefficients extracted from Raman data. Electron localization function analysis and crystal orbital Hamilton population further confirm the higher activity of the Sb³⁺ lone pair compared to Bi³⁺. Interestingly, despite the lower atomic mass of Sb relative to Bi, both compounds exhibit nearly identical acoustic-phonon cutoff frequencies. Consequently, both CuPbSbS₃ and CuPbBiS₃ display partially suppressed Umklapp scattering and comparable low lattice thermal conductivities at high temperatures, despite their compositional and structural differences.
SN - 0897-4756
SN - 1520-5002
ER -