Magnetic and structural properties of Mn(SCN)2(ROH)2 compounds

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Abstract
Three new members of the title series, where R=CH3, C2H5, i‐C3H7 or n‐C3H7, have been studied in addition to the previously examined ethanol homologue. A crystal structure for the methanol compound reveals a two‐dimensional network of manganese ions bridged by thiocyanate groups with methanols separating they layers. The situation is somewhat similar to that occurring for the ethanol compound, in which magnetic quasi‐two‐dimensionality was apparent. On the other hand, for the isopropanol compound a crystal structure suggests more nearly one‐dimensional magnetic character. Weiss constants in Curie–Weiss fits to high‐temperature data are −22.4, −20.9, −20.5, and −37.2 K for the methanol, ethanol, n‐propanol, and isopropanol systems, respectively. The susceptibilities exhibit broad maxima at about 12.7 K for the methanol and n‐propanol systems and about 16.0 K for the isopropanol system. All but the isopropanol exhibit a phase transition at about 10 K. For the methanol and ethanol systems weak ferromagnetism occurs below the ordering temperature; this appears not to occur for the n‐propanol system. Susceptibility data are analyzed on the basis of two‐dimensional (methanol, n‐propanol) or one‐dimensional (isopropanol) S=5/2 antiferromagnetic Heisenberg models. The exchange interaction is substantially stronger in the isopropanol than in the other members of the series.