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An oxygen-stoichiometric, B-site-ordered perovskite Ca2Fe1.1Mn0.9O6 (CFMO) with alternate stacking of Fe and Mn layers was obtained through topochemical oxidation of the corresponding brownmillerite phase under high pressure in the presence of KClO4. The structure crystallizes in the P21/m space group with a doubling of the cell along all three crystallographic axes. Mossbauer spectroscopy, susceptibility, and resistivity measurements suggest ferromagnetic interactions between Fe4+(d4) and Mn4+(d3) along [001] through a double-exchange mechanism, a situation similar to half-doped manganese perovskite oxides. Upon cooling, CFMO exhibits a ferrimagnetic transition below Tc = 90 K, likely accompanied by a charge disproportionation of the iron site, 2Fe4+ → Fe3+ + Fe5+. A reasonably good magnetoresistivity of 27 % was observed below Tc.

Ten types of neutral charge transfer (CT) complexes of coronene (electron donor; D) were obtained with various electron acceptors (A). In addition to the reported 7,7,8,8-tetracyanoquinodimethane (TCNQ) complex of 1:1 stoichiometry with a DA-type alternating π column, TCNQ also afforded a 3:1 complex, in which a face-to-face dimer of parallel coronenes (Cor-As) is sandwiched between TCNQs to construct a DDA-type alternating π column flanked by another coronene (Cor-B). Whereas solid-state (2)H NMR spectra of the 1:1 TCNQ complex formed with deuterated coronene confirmed the single in-plane 6-fold flipping motion of the coronenes, two unsynchronized motions were confirmed for the 3:1 TCNQ complex, which is consistent with a crystallographic study. Neutral [Ni(mnt)2] (mnt: maleonitriledithiolate) as an electron acceptor afforded a 5:2 complex with a DDA-type alternating π column flanked by another coronene, similar to the 3:1 TCNQ complex. The fact that the Cor-As in the [Ni(mnt)2] complex arrange in a non-parallel fashion must cause the fast in-plane rotation of Cor-A relative to that of Cor-B. This is in sharp contrast to the 3:1 TCNQ complex, in which the dimer of parallel Cor-As shows inter-column interactions with neighboring Cor-As. The solid-state (1)H NMR signal of the [Ni(mnt)2] complex suddenly broadens at temperatures below approximately 60 K, indicating that the in-plane rotation of the coronenes undergoes down to approximately 60 K; the rotational rate reaches the gigahertz regime at room temperature. Rotational barriers of these CT complexes, as estimated from variable-temperature spin-lattice relaxation time (T1) experiments, are significantly lower than that of pristine coronene. The investigated structure-property relationships indicate that the complexation not only facilitates the molecular rotation of coronenes but also provides a new solid-state rotor system that involves unsynchronized plural rotators.

Single crystals of the new compound KCuMoO4(OH) are hydrothermally synthesized from aqueous solutions of Cu(NO3)2 and K2MoO4 (autoclave, 433 K followed by slow heating to 493 K in 240 h).

The oxygen-stoichiometric, B-site-ordered perovskite Ca2Fe1.1Mn0.9O6 with alternate stacking of Fe and Mn layers is prepared by reaction of Ca2Fe1.1Mn0.9O5 with KClO4 in a molar ratio of 1:0.5 (gold foil, 4 GPa, 550 °C, 45 min).

The title compound is obtained from stoichiometric amounts of the elements (evacuated silica tube, 900 °C, 40 h; quenching).

MnCu3V4O12 is prepared by high pressure solid state reaction of MnO, CuO, and VO2 (Pt capsule in high-pressure cell, 12 GPa, 1373 K, 20 min).