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In a recent study (2) the heats of formation of a series of sodium chloridesodium bromide solid solutions were determined. At the time it seemed desirable to subject the several solid solutions to x-ray diffraction analysis so that some idea of their homogeneity and physical state might be obtained. In addition, there was some interest in ascertaining how nearly additive the lattice spacings and molar volumes are for this system. EXPERIMENTALThe preparation and analysis of the eleven samples studied (the two pure salts and nine solid solutions) have been described (2).X-ray powder diffraction patterns of these samples were made with a cylindrical camera of 171.9 mm. effective diameter, employing the Straumanis (5) technique. Unfiltered radiation from a sealed copper tube fitted with beryllium windows was used to reduce the exposure time. The general procedure followed in making the diffraction patterns and the mode of preparation of the cylindrical, 0.7 mm. diameter powder specimens of the samples are described elsewhere (4). To protect the prepared specimens from moisture, as well as to improve their mechanical strength, they were given a collodion coating by dipping into a diluted solution of flexible collodion. All samples and prepared specimens were stored in a desiccator over anhydrous calcium chloride when not in use. EXPERIMENTAL RESULTSPreliminary examination of the diffraction patterns indicated that all the solid solutions were single-phase, homogeneous, crystalline materials. The diffraction lines appeared uniformly sharp for the several solid solutions, as well as for the two pure salts. The patterns for the solutions showed no signs of lines characteristic of either of the pure constituents and all of the observed lines could be accounted for by assuming the existence of a single solid solution of fixed composition. The Bradley and Jay (1) extrapolation method was applied to the backreflection diffraction lines to obtain the lattice spacings (cation-cation distance) given in table 1. The variation of the lattice spacing with composition is shown in figure 1.

As positive means for identifying alkylated phenols, the authors have prepared phenyl isocyanate derivatives of a large number of phenols, and in this paper present tables of melting points and x-ray powder diffraction data. ASA result of recent developments, considerable quantities of alkylated phenols are finding use in the preparation of synthetic plastics, rubber, germicides, fungicides, and related substances. Because of this increasing interest in alkylated phenols, the authors have undertaken to develop an easy and positive means for their identification. One widely used method for such purposes is the determination of the characteristic melting point of the aryl N-phenylcarbamate formed by the reaction of a phenol with phenyl isocyanate. As this procedure has been shown to be authors No. formula Name 29 C»HnO 2-Cyclohexylphenol 111.5 30 CiiHuO 4-Cyclohexylphenol 145.5 31 CiiHuO 2-tert-A myl-4-methylphenol 4 (or 6)-

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