The suspension rheology of hematite in the ionic liquid Ecoeng TM. 212 was studied in detail and compared to the pure ionic liquid. This is the first report on the rheological behavior of suspensions in ionic liquids, and it is postulated that colloidal stability and rheology must be considered to understand these results, and to overcome limitations on the production of nanosized particles in industrial applications. Concentrated suspensions of particles in the nanometer range show non-Newtonian flow behavior including shear thinning and shear thickening. These phenomena are mainly caused by particle-particle interactions in the suspension, and control of these interactions is critical. The influences of temperature and solid concentration on flow behavior were shown for the pure liquid and the suspensions. It is seen that the ionic liquid follows the Arrhenius equation for non-associating electrolytes. It is possible to shift all hematite suspension curves to a master curve according to the model of Gleißle and Baloch. Furthermore, the flow behavior of the suspensions can be modeled with the well-known Herschel-Bulkley plot. A 10 wt % suspension of Fe 2 O 3 follows Newtonian behavior over the entire range, similar to the pure ionic liquid. It is believed that the ionic liquid has an influence on the stability of the particles, leading to a decrease of attractive particle-particle forces.

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C14H14N2NiO6, orthorhombic, Pbca (No. 61), a = 7.914(1) Å, b = 12.020(2) Å, c = 15.718(3) Å, V = 1495.3 Å3, Z = 4, Rgt(F) = 0.026, wRref(F2) = 0.062, T = 293 K.

Silicon nanoparticles were dispersed for 24 hours in 1‐butanol using a stirred media mill. Via this process intrinsically stable suspensions (in regard to aggregation) of Si nanoparticles were produced after 6 hours of dispersing. The evolution of morphology, particle size and structure was investigated by dynamic light scattering, X‐ray diffraction, Raman spectroscopy and high resolution transmission electron microscopy as a function of dispersing time. The average crystallite size decreased from about 18 nm down to about 10 nm within 24 hours of milling as determined by X‐ray diffraction and Raman scattering measurements. In addition careful analysis of the Raman spectra revealed a decrease of the crystalline volume fraction from 75% down to 24% and a corresponding increase of the amorphous phase. The microstructural development with varying crystallite size and crystalline volume fraction was directly confirmed by transmission electron microscopy measurements. Elemental analysis showed an increase of oxygen content that was directly proportional to the increase in specific surface area of the silicon nanoparticles during the dispersing process. The surface chemistry of the Si nanoparticles was analyzed by diffuse reflectance infrared Fourier transform spectroscopy that indicated vibrational bands of HSi–Si3–x Ox , SiOx , and residual 1‐butanol. The final product of the dispersing process seems to be a two‐phase mixture of amorphous Si and Si nanocrystallites covered with SiOx on the surface. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

C11H14CuN4O7, triclinic, P1̅ (no. 2), a = 7.522(2) Å, b = 9.754(3) Å, c = 11.349(3) Å, α = 108.87(3)°, β = 96.53(3)°, γ = 111.55(3)°, V = 706.8 Å3, Z = 2, Rgt(F) = 0.027, wRref(F2) = 0.063, T = 293 K.