Starker Pseudo‐Jahn–Teller‐Effekt in der Struktur von pyH[MnF₂(C₂O₄)(H₂O)₂]

Abstract

The first crystal structure of an oxalato‐fluoromanganate(III) was determined for pyH[MnF2(C2O4)(H2O)2]: monoclinic, space group I2/a, Z = 4, a = 7.2260(5), b = 15.2398(8), c = 9.916(7) Å, β = 98.22(5)°, R = 0.0297. The pyridinium salt crystallized from hydrofluoric acid solution at low temperature and in the dark. The structure of the anion shows octahedral coordination of MnIII with cis‐position of the fluorine ligands opposite to the bidentate bonded oxalate anion, and remarkable elongation of the H2O–Mn–OH2 axis due to a strong pseudo‐Jahn–Teller effect. The pyridinium cation is fixed to the oxalate anion by a bifurcated hydrogen bond. The anions are linked by strong hydrogen bonds O–H···F and O–H···O to form a 3D network.