The effects of adding Sb and In to pyrolytic SnO2 films were investigated. The large rise in resistivity for larger additions of Sb was studied using x‐ray diffraction, effects of heat‐treatment, determination of activation energy, and scanning electron microscopy. These results indicate that the rise is caused by a gradual loss of crystallinity and demonstrated the important effects of thermal history on the films' structure and electrical characteristics.

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COMPOUNDS of the type XYZ, or XY,Z,, where X and Y are different cations and Z is a chalcogen ion, e . g . BaTiS,, (Zn,Cd)Cr,S,, and CuCr,Se,, have important electronic and magnetic properties. Many observers have synthesized such compounds by reacting the elements directly in evacuated quartz tubes. The same technique has been used with mixed chalcogenides,' and the addition of halide fluxes has greatly improved the technique.* Conversion of a complex oxide to a complex chalcogenide by the use of CS, gas at high temperature has also been demonstrated.3 With these techniques, control of crystal or particle size and distribution is very difficult, particularly because of the high temperatures involved.Electronic and magnetic properties of powders, or bulk solids derived therefrom, are extremely dependent on particle (or grain) size, shape, and size distribution. Grain size must be controlled at approximately single-domain size to optimize properties such as photomagnetism, dielectric constant, and magnetic coercivity .A method was sought, therefore, that would permit precipitation of such compounds directly at low temperatures with good stoichiometric control and that would result in very fine, uniform particles suitable for direct use or for easy sintering to bulk bodies. Nonaqueous solutions are desirable because many complex chalcogenides are hydrolyzed by water. Solutions of stearates, which are readily available, in organic solvents are suitable.Initially, in an attempt to prepare CuCr,Se,, a stream of H,Se gas (prepared by reacting water and AI,Se3) was bubbled into a dry solution of Cu and Cr stearates in xylene. The black amorphous precipitate produced could be converted into crystalline CuCr, Se, by heating it to 300°C in evacuated tubes. This result suggested that, if precipitation could be conducted at =300"C, the crystalline spinel might be produced directly. Furthermore, the handling of H,Se gas was unpleasant and awkward. Since Se will dehydrogenate sterols at -3OO"C, giving aromatic hydrocarbons and H,Se (a method used for their characterization), an internal generation was considered.Such apreparation was attempted: 23.32 g (0.05 mol on the basis of analyzed Cu) of Cu stearate and 119.02 g (0.10 mol on the basis of analyzed Cr) of Cr stearate with 35 g sitosterol* and 23.69 g Se chips (0.2 mol+ 50% excess) were stirred into 350 ml of nujol in a 3-1 reaction vessel and slowly heated to 330°C. A clear solution was obtained, since water was drivenoff at <

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