Ilisulphide of Nickel (NiS,). Carbonate of nickel is strongly ignited with sulphur and carbonate of potash, and the residue well washed with water. It is soft to the touch, and of dark iron-gray colour.
l'horphide of Nickel (NiP) in formed by the action of phosphorus upon nickel heated to redness; the resulting compound is whitish, brittle, and is decomposed when exposed to heat and air. It is more fusible than the metal, and, and according to Pelletier, is composed of 17 phosphorus + 83 nickel ; while Lainpadius states it composition to be 13 phosphorus + 87 nickel.
Cyanide of Nickel (NiCy) is prepared by adding a soluble cyanide to a solution of nickel, or when hydrocyanic acid is mixed with acetate of nickel.
Nickel is a grayish or greenish compouud, which is precipitated when ferrocyanido of potassium ie added to the salts of nickeL The ferriryanirlc is yellowish green.
Nitrate of Nickel fNiO, NO,) may be prepared by dissolving either the metal or its oxide in dilute nitric acid. The solution is of a fine green colour, and by evaporation yield,' a deliquescent salt, containing six equivalents of water of crystallisation sulphate of Nickel (NiO,SU,+ 7Aq.) is easily procured by dissolving the oxide or hydrate in dilute sulphuric acid ; a green salt is obtained, which leadily crystallines in two different primary forms ; first in rhombic prismn, and than by exposure to light in regular octahedra, the original crystals becoming opaque hut retaining their prismatic outline. A double sulphate of potash and nickel (NiO, SO, + KO SO, + 6Aq) readily crystallises out on evaporating a solution of the mixed rulphates.
The carbonates of rarir/ are mostly basic, containing variable pro. portions of hydrated oxide. They are precipitated when an alkaline carbonate is added to a solution of nitrate, or other salt, of nickel.
Alloys of Skid :— Arsenic readily combines with Nickel, and the compound remains undecomposed at a very high temperature. It does not obey the magnet. Potassium and Nickel combine by fusion.
Antimony and Nickel form an alloy of a lead-colour.
Zinc and Nickel form a white brittle alloy, which enters into the composition of the pack font' of the Chinese.
Tin and Nickel give rise to a white brittle alloy, which burns at a high temperature.
Cobalt and Nickel readily fuse together.
Mercury and Nickel have not been combined.
Copper, Zinc, and Nickel form a white alloy, of late years much employed under tho name of Genuate Seven.
!rots and Ilickd occur associated in meteoric stones. The following table exhibits the centesimal amounts of the two metals in some well authenticated specimens.
1. From Clairborne in Alabama. 2. The Pallas meteoric iron from Siberia. 3. From Cap ; specific gravity, 7.665. 4. From Levarto ; specific gravity, 7198. 5. From Bohundlitz in Bohemia.
Tests for nickel. The solutions of nickel salts have a rich green colour. They are distinguished by giving—no precipitate with eul phuretted hydrogen; black with sulphide of ammonium ; green with a caustic alkali, not altering on exposure to air; and green pith ammonia, forming in excess a bright blue solution.
Estimation of nickel. This is generally performed in the state of protoxide, which contains per cent. of metal. It is precipitated from solution by potash, and must be many times washed with hot water to thoroughly remove all the alkali. According to Field, nickel is best precipitated as peroxide. The solution is boiled with hypo chlorite of soda in a beaker, care being taken to prevent the peroxide attaching itself to the sides of the vessel. This precipitate is easily washed, and on ignition to whiteness is reduced to protoxide, and in that state be weighed. Liebig separates nickel from cobalt by boil ing the solution of their poteesio.cyauides with finely lovigated per oxide of mercury ; the nickel salt is then decomposed and the hydrated oxide of that metal precipitated, while the cobalticyanide of potassium remains in solution along with cyanide of mercury.