High-Pressure Synthesis of A2NiO2Ag2Se2 (A=Sr, Ba) with a High-Spin Ni2+ in Square-Planar Coordination

Published

January 14, 2019

Author(s)

Yuki Matsumoto, Takafumi Yamamoto, Kousuke Nakano, Hiroshi Takatsu, Taito Murakami, Kenta Hongo, Ryo Maezono, Hiraku Ogino, Dongjoon Song, Craig Brown, Tassel Cedric, Hiroshi Kageyama

Abstract

Square-planar coordinate Ni²⁺ ions in oxides are exclusively limited to a low spin state (S = 0) owing to extensive crystal field splitting. Here we report layered oxychalcogenides A₂NiO₂Ag₂Se₂ (A = Sr, Ba) with the S = 1 NiO₂ square lattice. The structural analysis revealed that the Ni²⁺ ion is underbonded by a significant tensile strain from neighboring Ag₂Se₂ layers, leading to a reduction of the crystal field energy. Ba₂NiO₂Ag₂Se₂ exhibits a G-type spin order at 130 K, indicating fairly strong in-plan interactions. The high-pressure synthesis employed here possibly assists the expansion of NiO₂ square lattice by taking the advantage of a difference in compressibility in oxide and selenide layers.

Citation

Angewandte Chemie-International Edition

Volume

58

Issue

3

Pub Type

Journals

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Keywords

neutron diffraction, high pressure synthesis, X-ray diffraction

Citation

Matsumoto, Y. , Yamamoto, T. , Nakano, K. , Takatsu, H. , Murakami, T. , Hongo, K. , Maezono, R. , Ogino, H. , Song, D. , Brown, C. , Cedric, T. and Kageyama, H. (2019), High-Pressure Synthesis of A₂NiO₂Ag₂Se₂ (A=Sr, Ba) with a High-Spin Ni²⁺ in Square-Planar Coordination, Angewandte Chemie-International Edition, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=927211 (Accessed October 28, 2025)