On the isolation of the missing sulphur urea / by J. Emerson Reynolds.

Date:
[1869]
Catalogue details

Licence: Public Domain Mark

Credit: On the isolation of the missing sulphur urea / by J. Emerson Reynolds. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    111 preparing the salt juBt described, it will be observed that the urea must be kept in excess, but when the gold solution pre- ponderates, a reddish-yellow precipitate is produced, which decomposes so rapidly that it was found impossible to obtain it in a condition suitable for analysis; however, when we consider the constitution of the stable body already described, there appears to be some reason to believe that the red compound would turn out to be (CS)H,N,] Cl Uu. Cl J if it could be separated in a state of sufficient purity for examination. Platinum-compounds.—With platinum several compounds can be obtained. One of these bodies is highly characteristic of the new urea, and this I have studied ’^vith care. When a solution of tetrachloride of platinum, containing as little free acid as possible is added to a slight excess of the aqueous solution of the sulphur urea, a bulky, highly crystal- line, red precipitate is produced. The appearance of the pre- cipitate is remarkable, and under the microscope the compound is well characterised by the peculiar plumose appearance of the long prismatic crystals. The precipitate when produced as de^ scribed, must be quickly washed, first with water and then with alcohol. After pressing between folds of bibulous paper it must be rapidly dried at a temperature not exceeding 80° C. This platinum compound decomposes easily if left moist for some time, but keeps very well when thoroughly dry and free from tetrachloride of platinum. In the present instance I did not consider it safe to determine the sulphur and platinum only, but sought for direct evidence of the permanence of the molecule of the sulphur urea by the estimation of the nitrogen and chlorine in addition. Different preparations of the same salt were used in the fol-. lowing analyses: I. *5265 gim. of a very carefully prepared and quickly dried sample gave *2268 grin. Pt. •4035 grm. gave when oxidized with nitric acid *4 grm, BaSO^. II. *2729 grm. of another specimen gave, on ignition, grm. Pt.