while with the para compound it could not be formed. It could not be obtained by these methods, however, although the conditions were varied through wide ranges as to the excess of mercuric chloride, the amount of water used, the amount of acid added, and the degree of heat employed. This fact suggested the idea that there might be a greater possibility in the other direction with the para compound than with the ortho and meta, viz: that not only would a compound of the composition (C,H,NH3),HgCl. be formed, but also a possibility was suggested of going still farther in the proportion of the basic chloride to the mercuric chloride. With this in view experiments were next made using an excess of the basic chloride in gradually increasing amounts and under varying conditions. The results were invariably the same. The salt above described was formed in every case in quantity sufficient to use up the mercuric chloride and on evaporation the excess of paratoluidine hydrochloride crystallized from the solution. C2H,NH2HgCl, is therefore the formula for the only paratoluidine chloromercurate which it seems possible to make by these methods. This para salt, on account of its insolubility in cold water and the ease with which it can be crystallized, was probably the most satisfactory of the salts obtained. In its formation it was free from any admixture of the salts having different proportions of the chlorides-a fact which gave trouble, sometimes, working with the other salts. I. SUMMARY. These salts were found: Aniline dichloromercurate, C.H&NH3Hg,Cls; Dianiline chloromercurate, (C.HьNH3)2HgCl. ; The corresponding ortho- and metatoluidine salts and paratoluidine chloromercurate. 2. The corresponding salts of aniline; metatoluidine and orthotoluidine are very much alike in method of formation and in general properties, but differ somewhat in crystalline form. 3. The only paratoluidine salt formed is in properties much like the salts of the other bases which have a larger proportion of mercuric chloride. 4. Only these salts were obtainable by this method. MIXED DOUBLE HALIDES. No complete investigation has been made in this line, but work is still in progress. A few words will be given in order to show the nature and tendency of the work. 4 grams of orthotoluidine hydrochloride and 12 grams of mercuric bromide were weighed into a beaker with about 75 c. c. of water, and a few drops of hydrochloric acid added. (Numerous attempts with water only were failures). Some mercuric bromide crystallized out and was removed. On longer standing a salt crystallized in beautiful, glistening needles. These were uniform and regular in appearance, and were washed and dried. Analyses for mercury gave: I. 40.11% II. 40.51% Calculated for C2H,NH3HgBr2C1, Hg 39.76%. The existence of mixed halides of this order seems undoubted. The only difficulty is to get them in good condition. The above is given to show the possibility of their formation. When a chloride and bromide of the above kinds are mixed there are a number of possibilities-any of these salts may be formed HgBr2, HgCl2, CH,NH3HgBrCl2, CH,NH3HgBr,C1, and several others which might crystallize out. In some of the experiments all these possibilities seemed to be realized in the same beaker, judging from the various crystals formed. Some of the salts when heated in the mother-liquor melt to heavy oils which sink to the bottom of the beaker. These oils crystallize on cooling, but their nature has not been fully investigated. At present the most that can be said is that there is no doubt in the mind of the author as to the existence of the mixed salts, and the work on them will be continued. Chloromercurates of Elements of the Second Group. The following salts have been described by von Bonsdorff' Analyses are given for all except the zinc and strontium salts. The general method of preparation used by von Bonsdorff was to add mercuric chloride, as long as it would dissolve in the cold, to a saturated solution of the other chloride in water. Then by slow evaporation he would obtain two salts from the same solution, the second crystallizing after the first had been removed. His analyses were performed in a tube or bulb prepared for the purpose. The method in general was this: A weighed quantity of the salt to be analyzed was placed in this weighed bulb, and heated to drive off the water of crystallization which was collected in a calcium chloride tube and weighed, or allowed to escape, and estimated by the difference in weight of the bulb. Higher heat was now employed and the mercuric chloride driven off and estimated either by difference or by having it sublime in another part of the apparatus. The residue gave the basic chloride. Considering the method, his results agree very well indeed with calculated results. The chief difficulty in the prosecution of this work was, as has been the case with much of the double halide work, to get pure salts. The salts are so very soluble that when they do crystallize it is difficult to know whether you have a uniform salt or not. In this investigation more work was done upon the magnesium salt than upon any other. The methods of preparation were in general those used by Bonsdorff with some variations. The methods of analysis for mercury and chlorine were those given in the earlier part of this paper. Magnesium was precipitated as pyrophosphate, strontium as carbonate, and barium as sulphate. 1 Pogg. Ann. 17, 115. Magnesium Salt.-Following Bonsdorff's directions, mercuric chloride was added to a saturated solution of magnesium chloride. This was heated and filtered. On allowing to stand, or on evaporating slowly, a set of crystals were deposited just as Bonsdorff describes them. It is almost impossible to free this salt completely from the mother-liquor. The method pursued was to place it first on the filter-pump, and then quickly remove it and press it between thick folds of drying-paper by means of a press. The formation of the salt was tried a great many times and a great many products were analyzed. In order to learn whether the water of crystallization could be driven off by heat or not, about a gram of the salt was carefully weighed and put into an air-bath. Heated for 18 hours at not over 105° it lost 20.79% in weight. Continuing the drying for 15 hours more with the temperature at no time above 102° the salt lost 46%. Another specimen lost 20% while at a temperature of not over 100°. A third specimen lost 12.6% when dried at a temperature of not over 90°. Mercuric chloride itself lost about 20% dried at 90° or below in 15 hours, and over 65% when at the same temperature for two or three days. From these experiments it will be seen that it is impossible to determine the water of crystallization by heating. As the salt does not lose its water of crystallization over sulphuric acid it could not be determined in this way. The average of a number of analyses of the better specimens obtained gave the following results: Bonsdorff's analyses calculated with the same atomic weights give : I. Hg. 60.08%, Mg. 2.46%, Cl. 28.52%. II. Hg. 59.68%, Mg. 2.43%, Cl. 28.28%. From these figures he gives the formula with five molecules of water. The formula with six molecules, as is seen, agrees better with the results obtained at this time, but the results are not sufficiently accurate to say with certainty that it has six molecules of water. Bonsdorff describes a salt obtained by evaporation of the mother-liquor from this salt. No such salt was obtained, although many and varied attempts were made to obtain it. Solutions were evaporated slowly for days, others more slowly for weeks, and others still more slowly for months, and no such salt was formed. After the first salt ceased to separate in good form all other crystallizations were mixtures of such a nature as to preclude separation. They were, as nearly as could be learned, mixtures of the first salt and one of the chlorides added in the first place. Attempts were also made to form other salts by using varying proportions of the other two chlorides and by varying the amount of acidification and of dilution, etc.-all with no success. Some investigations were begun on the chlorides of the other elements of the group. On account of the unfinished condition of the work, only the compounds of strontium and barium will be mentioned. Strontium Salt.-The chlorides of strontium and mercury were brought together as in making the magnesium salt. A crystallized salt was obtained which is very soluble. It crystallizes in transparent plates, but sometimes in very delicate needles or hairs which project from the top of the solution. This latter was the case when a solution at the point of saturation stood in the air. In the morning there would be a crop of these hairs which would dissolve by the heating of the room during the day and re-form again in the night. Four analyses of good specimens of this salt gave : Hg. I. 50.48%. II. 50.59%. III. 50.49%. IV. 50.35%. |
