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Substitution of La(3+) by Sr(2+) in the double perovskite La(2)CoTiO(6) yields materials of the La(2-x)Sr(x)CoTiO(6) series showing a significant amount of trivalent cobalt ions when prepared at ambient atmosphere. The as-prepared compounds can be reduced in severe conditions retaining the perovskite structure while inducing the formation of a large amount of oxygen vacancies. The limit of aliovalent substitution in this series was found to extend up to x = 1. For substitution of La(3+) up to 15% cobalt and titanium are ordered, though the order is progressively lost as x increases; for x≥ 0.30 no ordering is observed as evidenced by magnetic measurements. The ability of these materials to present either cobalt ions in a mixed oxidation state or large amounts of anion vacancies depending on the atmosphere makes them interesting to be further investigated regarding their electrical and electrochemical properties, and hence, their usefulness in some electrochemical devices.

The compound [Cu(cyclam)(TCNQ)2](TCNQ) (cyclam = 1,4,8,11-tetraazacyclotetradecane, TCNQ = 7,7,8,8-tetracyanoquinodimethane) has been obtained in two different crystallographic forms, isomers 1 and 2. Crystal data for isomer 1:  triclinic, P1̄, a = 7.855(6) Å, b = 10.267(2) Å, c = 14.424(3) Å, α = 95.42(2)°, β = 102.18(5)°, γ = 109.74(3)°, Z = 1. Crystal data for isomer 2:  triclinic, P1̄, a = 8.165(1) Å, b = 9.918(3) Å, c = 13.278(3) Å, α = 83.91(2)°, β = 78.31(2)°, γ = 79.22(2)°, Z = 1. Both isomers show the same copper environment and oxidation states in the TCNQ molecules, and the only difference is observed in the stacking of the latter groups. The main common feature is the presence of parallel chains of copper macrocycle units linked by dimeric (TCNQ)2 2-, which coordinates to the metal. These chains are joined in isomer 1 by one neutral TCNQ molecule oriented parallel to the anionic TCNQ dimers and overlapping with two of them creating a bidimensional network. In contrast, the neutral TCNQ in isomer 2 is rotated about 70° relative to the anionic dimers and overlaps with four different chains, extending the interaction in a tridimensional way. The spectral and solid state conductivity data show electronic localization on the dimers (TCNQ)2 2- in both isomers with a weak semiconducting behavior. The magnetic behavior of both isomers can be interpreted as the sum of contributions from the metal and a thermally activated triplet state for the dimerized anions. The latter contribution is favored by the π overlap of the neutral TCNQ molecules, since the analogous derivative [Cu(cyclam)(TCNQ)2], only with anionic dimers, shows a strong antiferromagnetic coupling inside the dimers and no appreciable contribution to the bulk magnetic susceptibility is observed.

A new oxide of the Ruddlesden–Popper series in the (Eu,Sr)n+1(Co,Fe)nO3n+1 system has been isolated and structurally characterized.

We report the rich magnetic behaviour of Sr2CoNb1-xTixO6 (0 ≤ x ≤ 0.5) oxides as a result of their complex microstructure. Although these oxides show an average simple-cubic perovskite structure, they present a flexible microstructure due to short-range ordering between Co/Ti and Nb cations in the perovskite B-sites. The microstructure consists of double-cubic perovskite domains grown in a simple-cubic perovskite matrix. The size and number of the double-cubic perovskite domains decrease as the Ti content increases. As a result of aliovalent substitution of Nb(5+) by Ti(4+) in the parent Sr2CoNbO6 mixed-valence Co(3+)/Co(4+) oxides are obtained. A spin glass-like state has been observed at low temperatures for all the series, with freezing temperatures increasing with the Ti-content in the range 22 to 33 K. Furthermore, the x = 0.3 and x = 0.5 samples show non-interacting superparamagnetic particle-like dynamics associated with relatively high amounts of Co(4+), with "blocking temperatures" of 13 and ∼16 K, respectively. The complex magnetic behaviour of the title oxides seems to be connected with the clustering of magnetic Co(3+) and the distribution of Co(4+) as a result of the microstructure.