Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The characterization of the crystal structure, phase transitions, magnetic structure and dielectric properties has been carried out on [CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>][Co(COOH)<jats:sub>3</jats:sub>] (<jats:bold>1</jats:bold>) perovskite‐like metal–organic compound through variable‐temperature single‐crystal and powder neutron and X‐ray diffraction and relative permittivity measurements. The paraelectric to antiferroelectric‐like phase transition observed at around 90 K is triggered by a structural phase transition; the structural studies show a change from <jats:italic>Pnma</jats:italic> space group at RT (<jats:bold>1A</jats:bold>) to <jats:italic>P</jats:italic>2<jats:sub>1</jats:sub>/<jats:italic>n</jats:italic> space group at low temperature (<jats:bold>1B</jats:bold>). This phase transition involves the occurrence of small distortions in the framework and counterions. Neutron diffraction studies have shown a magnetic order showing spontaneous magnetization below 15 K, due to the occurrence of a non‐collinear antiferromagnetic structure with a weak ferromagnetic component, mainly due to the single‐ion anisotropy of the Co<jats:sup>II</jats:sup> ions.</jats:p>