As we have already seen, Vogel proposed to obtain chlorine by the decomposition by heat of cupric chloride, and to reconvert the resulting cuprous chloride into the cupric salt by treatment with hydrochloric acid.
A small proportion of cuprous chloride is also formed, and special precautions have to be taken to prevent the extensive formation of this compound which is dissolved only with difficulty.
This method may even be taken advantage of for the preparation of chlorine andcuprous chloride, CuCl.
It is soluble in boiling hydrochloric acid, but it is not reprecipitated by water, as is the case with cuprous chloride.
Cuprous chloride, CuCl or Cu2Cl2, was obtained by Robert Boyle by heating copper with mercuric chloride.
Cuprous fluoride, CuF, is a ruby-red crystalline mass, formed by heating cuprous chloride in an atmosphere of hydrofluoric acid at 1100 deg.
A phosphide, Cu3P2, is formed by passing phosphoretted hydrogen over heated cuprous chloride.
Cuprous oxide, Cu2O, occurs in nature as the mineral cuprite (q.
The precipitation of the copper from the solution, in which it is present as sulphate, or as cuprous and cupric chlorides, is generally effected by metallic iron.
It may be prepared by heating cuprous sulphide with sulphur, or triturating cuprous sulphide with cold strong nitric acid, or as a dark brown precipitate by treating a copper solution with sulphuretted hydrogen.
Sulphur dioxide is then blown in, and the precipitate is treated with iron, which produces metallic copper, or milk of lime, which produces cuprous oxide.
In the process of oxidation, a certain amount of cuprous oxide is always formed, which melts in with the copper and diminishes its softness and tenacity.
A solution of cuprous chloride which has absorbed CO gives it up on being treated with potassic bichromate and acid.
The solution of cuprous chloride is prepared by dissolving 10.
Volumetric methods are used, but the uncertainty of the end of the reaction has led to the suggestion of special indicators, or of determining the amount of cuprousoxide gravimetrically.
Carbon monoxide is absorbed by a solution of cuprous chloride in hydrochloric acid or, better, in ammonia.
When small in amount, it is better to estimate as carbon dioxide by burning with oxygen and absorbing in potash; when large in amount, the bulk is absorbed in ammoniacal cuprous chloride and the residue burned.
Frank of Charlottenburg, who finds that a concentrated solution of cuprous chloride in an acid, the liquid being made into a paste with kieselguhr, is the most effective.
The most important cuprous compound is the oxide (Cu{2}O), which occurs in nature as ruby copper or cuprite.
By treating cuprous oxide with different acids a number of cuprous salts can be made.
Silver forms two oxides but only one series of salts, namely, the one which corresponds to the mercurous and cuprous series.
Since they are so much more familiar than the cuprous salts, they are frequently called merely copper salts.
Copper, like iron, forms two series of compounds: in the cuprous compounds it is univalent; in the cupric it is divalent.
The cupric salts are much the more common of the two, since the cuprous salts pass readily into cupric by oxidation.
On the other hand, a small amount of sugar may be present and yet fail to show the reaction, because the cuprous oxide is held in solution by certain substances.
Finally, excess of glucose will also hold in solution cuprous oxide, so that the suspected urine should not be added in too large a quantity at a time, but rather drop by drop.
In a general way, according to the later authors, they were largely lead oxide, and contained from 5% to 20% cuprous oxide.
The blast is continued until the impurities are practically eliminated, and at this stage the molten metal contains a great deal of dissolved cuprous oxide, which must be reduced.
This cuprous oxide mostly melts and diffuses through the metallic copper, and readily parting with its oxygen to the impurities further facilitates their complete oxidation.
Alkaline copper solutions yield a precipitate of red cuprous oxide; ammoniacal silver solutions give silver mirrors; alkaline solutions of mercury salts are reduced to metallic mercury, etc.
Cuprous carbide or acetylide is the reddish brown amorphous precipitate which is the ultimate product obtained when acetylene is led into an ammoniacal solution of cuprous chloride.
Cuprous chloride is used as a solution in strong hydrochloric acid mixed with ferric chloride, and similarly absorbed in kieselguhr.
In contact with neutral or acid solutions ofcuprous salts acetylene yields various double compounds differing in colour and crystallising power; but according to Chavastelon and to Caro they are all devoid of explosive properties.
Copper is a metal which yields two series of compounds, cuprous and cupric salts, the latter of which contain half the quantity of metal per unit of acid constituent that is found in the former.
The process must be carried out in the order named, as the pyrogallol solution will also absorb carbon dioxide, while the cuprous chloride solution will also absorb oxygen.
The greatest care should be taken in preparing the cuprous chloride solution in making analyses and it must be known to be fresh and capable of absorbing CO.
Mallet procures oxygen in large quantities as follows:--He puts into retorts revolving on horizontal axes, a mixture of cuprous chloride, and kaolin or sand.
Copper salts liberate iodine; but when this has been removed by boiling and the cuprous iodide has been filtered off there is no further interference.
Copper forms two classes of salts, cuprous and cupric.
There is a method of determination by fusing 5 or 10 grams in a brasqued crucible, and counting the loss as oxygen; and another method for the determination of cuprous oxide based on the reaction of this substance with nitrate of silver.
Boiling with nitric acid converts the lower into the higher oxide; and powerful reducing-agents, such as cuprous chloride, have the opposite effect.
This is based upon the fact that when potassic iodide in excess is added to a strong solution of a cupric salt in a faintly acid solution, cuprous iodide is formed and an equivalent of iodine liberated.
All commercial copper carries oxygen; most of it is present as cuprous oxide, which is dissolved by molten copper.
When so altered, the solution will yield a more or less copious precipitate of cuprous oxide on merely boiling, and quite independent of the presence of glucose.
Yellow to brick-red cuprous oxide forms as a heavy precipitate if glucose is present.
His solution differs from that of Fehling in containing ammonia, which dissolves the cuprous oxide as soon as it is formed, yielding a colorless solution.
As suitable oxygen carriers the chlorides of copper have been found to give the best results, it being preferrable to use the copper in the form of a cuprous salt.
The metal itself is to a greater or less depth converted into cuprous oxide.
This rule is perhaps not invariable, for I have often found cuprous oxide present under the so-called spreading patina, but absent beneath one which is undoubtedly durable.
Mitzopulos[43] described the green patina of the copper alloys found in Mycene as malachite and atacamite upon a reddish layer of cuprous oxide.
Secondly, the cuprous oxide layer is in the crystallized state.
The cuprous oxide, which is generally regarded as unaffected by air, is perhaps drawn into further reaction through the agency of ammonia.
He discusses also the occurrence of the cuprous oxide layer which is said to have been described by Sage as early as 1779.
Green patina on a layer of cuprous oxide (Etruscan vase, Ant.
From the following considerations Wibel thinks that he is justified in his assumption that the layer of cuprous oxide is the result of reduction.
Firstly, by no means all bronzes which have been dug up, even though from the same excavation, show the layer of cuprous oxide.
A slow reaction takes place and a double compound of cuprous chloride and sodium chloride is formed.
