Bimetallic tris-oxalato-salts (n-C n H 2nϩ1 )PPh 3 M II Fe III (C 2 O 4 ) 3 (n = 3-7, M II = Mn, Fe) were prepared and the structures investigated by powder X-ray diffraction in order to study the evolution of the structure and magnetic properties as a function of alkyl chain length. The compounds all have the same two-dimensional honeycomb structure of M II and Fe III bridged by oxalate, with the organic cations lying between the metal-oxalate layers, whose separation ranges from 9.48 Å (n = 3) to 11.10 Å (n = 7) for the Fe II salts and 9.37 to 10.81 Å for Mn II . The compounds all behave as ferrimagnets, with magnetic parameters similar to the corresponding AM II Fe III (C 2 O 4 ) 3 with A = NR 4 ϩ , PPh 4 ϩ and T c s almost insensitive to interlayer separation. The Mn II salts exhibit uncompensated magnetisation below T c and the Fe II ones show Néel type N ferrimagnetism, with negative magnetisation at low temperature, the magnitude of which is influenced by the preparation conditions, due to vacancies in the Fe II sublattice.

3 ͔ between 10 and 30 K of broad sextets and doublets in the Mössbauer spectra and the paramagnetic scattering observed in the polarized neutron measurements indicate the coexistence of spin-correlated and spin-uncorrelated regions in the layers of this compound. The polarized neutron scattering profiles and the Mössbauer spectra yield the magnetic exchange correlation length and lifetime, respectively, and the combined results are best understood in terms of layers composed of random frozen, but exchange correlated domains of ca. 50 Å diameter at the lowest temperatures, of spin-correlated domains and spin-uncorrelated regions at intermediate temperatures, and of largely spin-uncorrelated regions above the Néel temperature as determined from magnetometry. The similarity of the Mössbauer spectra of (PPh 4 ) ͓Fe II Fe III (ox) 3 ͔ and (NBu 4 ) ͓Fe II Fe III (ox) 3 ͔ leads to the conclusion that similar magnetic exchange correlations are present in the latter compound.

Magnetic field driven transition from an antiferromagnetic ground state to a ferrimagnetic state in Rb0.19Ba0.3Mn1.1[Fe(CN)6]·0.48H2O Prussian blue analogue J. Appl. Phys. 112, 093903 (2012); 10.1063/1.4759361Huge influence of hydrogenation on the magnetic properties and structures of the ternary silicide NdMnSiHigh temperature neutron diffraction studies of 0.9 BiFeO 3 -0.1 PbTiO 3The M II and M III magnetic ions in the extended molecular network P͑C 6 D 5 ͒ 4 MnFe͑C 2 O 4 ͒ 3 form a two-dimensional honeycomb magnetic lattice. The Mn 2ϩ and Fe 3ϩ ions alternate in the extended network which is formed by the oxalate (C 2 O 4 ) ligands. These hexagonal layers are separated and charge compensated by large ͓P͑C 6 D 5 ͒ 4 ͔ ϩ ions, positioned in between the honeycomb layers. P͑C 6 D 5 ͒ 4 MnFe͑C 2 O 4 ͒ 3 orders magnetically at T N ϭ27(1) K. A full neutron spin polarization study of the neutron scattering cross section has been carried out which allows the unambigious separation of the magnetic cross section from the total diffraction process. The magnetic structure can be described with the magnetic Shubnikov group R3c. The magnetic moments are antiferromagnetically aligned along the c axis while the Mn 2ϩ and Fe 3ϩ ions form an antiferromagnetic alignment on the honeycomb lattice.

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