We report measurements of the dectrical resistivity, Hall coefficient, magnetoresistance, thermoelectric power, infrared reflectivity, and c-axis lattice parameter of single crystals of titanium disulfide Ti&+"S& with varying degrees of nonstoichiometry. The strong correlations we find between different measurements made on the same sample allow us to conclude that titanium disulfide is a semiconductor rather than a semimetal. Even though this fact is established, our most stoichiometric samples continue to exhibit metallic behavior, and the source of these conduction electrons is unknown. In addition, none of the scattering mechanisms examined here is capable of explaining the unusual temperature dependence of the electrical resistivity which varies as T' at low T and as T~a bove 100 K where y ranges from 1.85 for the least stoichiometric samples to 2.2 for the most stoichiometric.

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YNTHESIS of a glass from the composition K2C02-MgCO3 was reported by Eitel and Skaliks' and since then no systematic S attempts to form carbonate glasses have been reported.The highly symmetrical co3 group is not expected to be easily distorted and consequently should not lend itself readily to glass formation. Limited areas of glass formation, however, have been found with certain carbonate compositions and with other selected compositions where volatile compounds must take part in network formation.at 1 kilobar pressure in most instances, using samples contained in sealed noble metal capsules. After heat treatment and quenching, refractive indices of glasses were measured and infrared absorption spectra were obtained where desired. Relatively stable glasses were formed from 40, 50, and 60 mole % MgC03 compositions in the binary system KzC03-MgCOa. Refractive indices of these glasses are plotted in Fig. 1, with circles indicating stable glasses and crosses indicating partly devitrified samples. The indices are 4 to 5% lower than the mean value of the crystalline carbonates. Infrared spectra were also obtained and the spectrum of the K~C03.MgC03 glass (in the 2 to 13p region) was very similar to that of crystalline K2C03-MgC03 showing typical COS frequencies. The spectrum of the glass differs in having broader absorption maxima correspondingly shifted to slightly lower frequencies. No major change in coordination number of the C (e.g., 3 to 4) is, however, suggested foi the glass structure. The lowa refractive index and density of the glasses compared to the crystalline phases may, therefore, be a result of decrease in averape Mg coordination.3 Some samples containing small amounts of hydroxyl were found to devitrify, apparently through the formation of discrete hydroxyl complexes which interrupt the carbonate polymerization.The necessity of ions such as Mg2+, which may assume small coordination numbers, for stabilizing carbonate glasses seems to be further borne out by the limited conditions of glass formation observed with ternary compositions and with other binary mixtures. Glasses were produced on quenching the following compositions from 900" and 1 kilobar: 5 mole yo of either Mn-C 0 3 , PbCOa, or CaC03 added to 95 mole ' % KzCOs.MgCO3.Substitutions of 10% or greater in each instance, however, caused devitrification on quenching. A number of other binary systems were explored but crystallization took place during quenching. BaC03. Li2C03 gave very slightly devitrified glasses; the Li in this case may have a role similar to that of Mg, but is not as effective because of its lower charge. The BaC03-Li2COa mixtures, however, might be expected to form glasses when mixed with additional components. Some more complex systems of volatile constituents were investigated using component binary systems in which no glass formation was observed. The system CaFz-Ca(OH)z-CaCOs-BaS04 rather surprisingly contains a series of glass-forming compositions The reason for glass formation in this instance is not clear; the most obv...

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The magnetic susceptibilities of the insulating Magneli phases V30~, V407, V60~~, and V80~& have been measured at low temperatures.Due to a short-range-order effect V305 exhibits a broad maximum at 125 K, which is substantially higher than the Neel temperature, 76 K, of this compound. For V407 and V60~~the difference between the Neel temperature and the temperature of the maximum in the susceptibility is small. This excludes the possibility that a linearchain model discussed by Khattak et al. can explain the specific heat of these two compounds.The temperature derivative of the susceptibility for these two compounds has a maximum at the Neel temperature which corresponds to Fisher's relation. The susceptibility for V80~5 is nearly constant between 5.6 and 68 K, and depends on past history below 5.6 K, i.e. , whether the sample is being cooled or heated. However this temperature hysteresis is sample dependent. These experimental data cannot be accounted for by an ordinary antiferromagnetic transition in the insulating state and suggest another type of transition, The possibility of the existence of a mixed charge-density and spin-density wave is discussed, since this can explain qualitatively the experimental features found for V80&5.