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Updated: May 10, 2026

Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
Reversible high-temperature phase transition of a manganese(II) formate framework with imidazolium cations
Bi-Qin Wang1, Hai-Biao Yan, Zheng-Qing Huang
1School of Chemistry and Chemical Technology, Faculty of Light Industry, Hubei University of Technology, Wuhan, Hubei 430068, People's Republic of China. wangbq@sjtu.org
Abstract:
A new metal-formate framework, poly[1H-imidazol-3-ium [tri-μ2-formato-manganese(II)]], {(C3H5N2)[Mn(HCOO)3]}n, was synthesized and its structural phase transition was studied by thermal analysis and variable-temperature X-ray diffraction analysis. The transition temperature is around 435 K. The high-temperature phase is tetragonal and the low-temperature phase is monoclinic, with a β angle close to 90°. The relationship of the unit cells between the two phases can be described as: a(HT) = 0.5a(LT) + 0.5b(LT); b(HT) = -0.5a(LT) + 0.5b(LT); c(HT) = 0.5c(LT). In the high-temperature phase, both the framework and the guest 1H-imidazol-3-ium (HIm) cations are disordered; the HIm cations are located about 2mm sites and were modelled as fourfold disordered. The Mn and a formate C atom are located on fourfold rotary inversion axes, while another formate C atom is on a mirror plane. The low-temperature structure is ordered and consists of two crystallographically independent HIm cations and two crystallographically independent Mn(2+) ions. The phase transition is attributable to the order-disorder transition of the HIm cations.
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