Appendix I, Determination of random coincidence in a fast-slow coincidence circuit; Appendix II, Multiple scattering during measurements of S-directional distribution from polarized nuclei, of S-y-circular polarization correlation, and of S-y-directional correlation.

The present paper is devoted to the determination of the heats of reaction of lanthanum ions with halogen ions within a broad concentration range of hydrogen halides. The enthalpies of the interaction of lanthanum perchlorate with perchloric and halogen acids increase with the increasing of acid molality from one to eight. The enthalpies of the interaction between lanthanum and halogen ions in water solutions are endothermic and decrease in the sequence; Cl > Br > J. The values support the fact of formation of lanthanum chloride complexes and point to the possibility of forming bromide complexes, but the question of the existence of iodide complexes of lanthanum in aqueous solutions is left open.

Experimental data supporting lower valence halides of scandium were not found in the literature. Our investigation was of the phase diagram of the ScCl3-Sc system, and also the vapor pressure-composition isotherm (at 960 degree) for this system. Investigation of the ScCl3-Sc system presented particular difficulties in comparison with analogous systems for rare earth elements in that ScCl3 is highly volatile (boiling pt. = 967 degree); according to our data the vapor pressure is 512 mm Hg measured at 960 degree C. Furthermore, ScCl3 and its vapors react vigorously with quartz. Because of the mentioned extent of reaction in a quartz ampule, the inside was covered with a solid layer of metallic molybdenum for use with relatively large batches of ScCl3.