Both Raymond and Thomson remark that phosphuretted hydrogen water produces a black or dark brown precipitate in sulphate of copper. I have not found any precipitate from any of the salts of copper by the same means. But if the blue hydrate be first precipitated by lime water, and then the phosphuretted hydrogen water admitted, the hydrate is immediately converted into a dark olive, which in all probability is a phosphuret of copper. From some experiments I am inclined to believe that this compound is the deutophosphuret, or two atoms of phosphorus to one of copper; and hence the copper is to the phosphorus as 100 ∶ 33⅓.
13. Phosphuret of iron.
M. Pelletier formed a phosphuret of iron by both the methods above described for gold. He describes the phosphuret as very hard, of a white colour, striated and magnetic. He estimates, with some uncertainty, that 100 iron may combine with 20 phosphorus.
Berzelius produced a phosphuret of iron by reducing the phosphate of the metal by charcoal and heat. (An. de Chimie, July 1816). He describes it as having the colour of iron, brittle and slightly acted upon by the magnet. By his analysis it was constituted of 100 iron and 30 phosphorus. The true proportion probably would be one atom to one, or 25 iron to 9⅓ phosphorus; that is, 100 iron to 37 phosphorus.
Both Raymond and Thomson found that sulphate of iron yields no precipitate by phosphuretted hydrogen water; and I may add, that the precipitated oxide or hydrate is also unaffected by the same.
14. Phosphuret of nickel.
By projecting phosphorus amongst red hot nickel, Pelletier united 20 parts of the former to 100 of the latter. A part of the combined phosphorus, he observes, flies off on cooling, so that the above proportion may perhaps be too low. Theoretically one atom of nickel should combine with one of phosphorus; that is, 26 with 9⅓, or 100 with 36.
I find that neither the nitrate of nickel nor the hydrate are affected by phosphuretted hydrogen water.
15. Phosphuret of tin.
Margraff was the first who combined phosphorus and tin by fusing the metal along with fusible salt from urine (phosphate of ammonia). Pelletier succeeded also in this way, as well as by the direct one of projecting phosphorus into melted tin. The compound was of a white colour; it gained 12 per cent. of weight; but as part of the tin was oxidized and adhered to the crucible in form of glass, he conjectures that tin would take from 15 to 20 per cent. of phosphorus. The atom of tin being 52, and that of phosphorus 9⅓, the due proportion would be 100 tin to 18 phosphorus.