The properties of four completely saturated and one partially saturated salts consisting of methyl-tri-n-decylphosphonium cations and either chloride, chloride monohydrate, bromide, bromide monohydrate, or nitrate anions are reported. Their neat phase behavior has been examined by polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction. The monohydrates form smectic phases that persist in >90 °C ranges and extend from below room temperature; they are ordered, room-temperature ionic liquid crystals. The nitrate salt becomes liquid-crystalline above room temperature and the other two salts remain as soft solids to their isotropization temperatures. The locations of two solvatochromic dyes, Nile Red and 1,1-dicyano-2-[6-(dimethylamino)naphthylen-2-yl]propene, within the ionic assemblies have been approximated from UV/vis absorption and fluorescence spectra, and the temperature (phase) dependence of the conductivities and dielectric constants of some of the salts have been measured. Some comparisons with properties of isotropic, room-temperature ionic liquids are made.

The magnetic and transport properties of the Hong and Steinfink 1-dimensional barium iron sulfide phases BaFe 2 S 3 and Ba 6 Fe 8 S 15 were studied. The valence precise BaFe 2 S 3 phase (Fe 2+ ) is semiconducting with a nonmagnetic ground state due to strong intrachain antiferromagnetic coupling. However, short-range magnetic correlations and spin-glass-like behavior are found below 25 K, which gives rise to a magnetoresistive effect of 10% at 9 T. BaFe 2 S 3 is a rare example of a magnetoresistive ternary sulfide. The mixed valent Ba 6 -Fe 8 S 15 phase (Fe 2.25+ ) is also a semiconductor with a nonmagnetic ground state. Ba 6 Fe 8 S 15 shows similar spin-glass-like behavior but at a lower temperature (T f ) 15 K). Comparisons with other tetrahedrally coordinated iron sulfide phases and possible origins of the shortrange magnetic correlations are discussed.