Licence: Public Domain Mark
Credit: Qualitative chemical analysis / by C. Remigius Fresenius. 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.
147/526 page 123
![14 Boras and microcosmic salt dissolve imnganese compounds in theoutevgas or blowpipe flame to clear violet-red beads, which on in ine outti «a „ „ _iif„.t-red tint: they lose then- colour m the LtKXgral-'lC^^^^^^ LesquLide to protoxide The Wxb^d Appears black when containing a considerable portion of seWoxide o/manganese, but that formed by microcosmic salt never L JTts transparency; the latter loses its colour m the inner flame of the blowpipe far more readily than the former. § 108. c. Nickelous Oxide or Protoxide of Nickel, NiO [NiO]. 1 Metallic nickel in the fused state is silvery white, inclining to <n^ay; it is bright, hard, maUeable, difficultly fusible; it does not oxidize in the air at the common temperature, but it oxidizes slowly on ignition : it is attracted by the magnet and may itself become magnetic. It dissolves slowly in hydrochloric acid or dilute sulphuric acid on applying heat, with evolution of hydrogen. It dissolves readily m nitric acid. The solution contains a salt of protoxide of nickel. 2 Hydrate of protoxide of nickel is light green, and re- mains unaltered in the air, but is converted into green protoxide _ot nickel at a white heat. Both the protoxide and its hydrate are readily soluble in hydrochloric, nitric, and sulphuric acids; the protoxide crystaUized in octahecbons is, however, insoluble in acids, but dissolves m fusing bisulphate of potassa. Sesquioxide of nickel, NI3O3 [Nl^], is black; it dissolves in hydrochloric acid to protochloride with evolution of chlorine. By gentle ignition of the hydrate, carbonate, or nitrate, a residue of grayish-green colour is obtained consisting of the prot- oxide containing sesquioxide. 3. Most of the salts of protoxide of nickel are yellow m the anhydrous, green in the hydrated sta,te; their solutions are light green. The soluble neutral salts slightly redden litmus-paper. The salts of nickel containing volatile acids are as a rule easily decomposed by ignition; the sulphate, however, will stand a low red heat. 4. SvLLphuretted hydrogen does not precipitate sokitions of nickel salts of strong acids in presence of free acids; in the absence of a free acid, a small portion of the nickel gradually separates as black sulphide of nickel, NiS [NiS].—Acetate of protoxide of nickel is not precipitated, or but very slightly in presence of free acetic acid; but in the absence of free acid, however, the greater part of the nickel is thrown down by long-continued action of sulphuretted hydrogen; moreover, if the solution contain sufficient of the acetate of an alkali, sulphuretted hydrogen will precipitate the whole of the nickel from the hot solution, even when excess of acetic acid is present. 5. Sulphide of ammoniiim in neutral, and sulphuretted hydro-', gen in alkaline solutions, produces a black precipitate of hydrated sulphide of nickel, NiS [NiS], which is not altogether insoluble in sulphide of ammonium, especially if the latter contains free ammonia; the solution from which the precipitate has been thrown down is usually therefore of a brownish colour, and yields a slight precipitate of sulphide of nickel, on being neutralized with acetic acid and warmed. The presence of chloride of ammonium, and still more of acetate of](https://iiif.wellcomecollection.org/image/b21966953_0147.jp2/full/800%2C/0/default.jpg)
