in 



COPPER. 



COPPER. 



M 



manufacture of pigments. Luge quantities of it are also employed in 

 agricultural district* to steep seed-corn in, it being found that this i 

 an effectual rmiedy againet the disease in whet called * smut." For 

 the latter purpose, however, a very impure sulphate of cop|r is fre- 

 quently need ; obtained by evaporating the Birmingham " pickle," or 

 " dipping liquor," of the bnutirr and coppcnmith. This liquor U an 

 acid volution into which manufactured hrara article* hare been dipper) 

 in order to render them perfectly clean before lacquering, varnishing, Ac. 

 The sulphate thus obtained coU some shillings lea* per cwt. than the 

 purer variety, but more of it must be used to produce the desired 

 ,:', 



D<mUe t*>iJ<atrt of copper and alkali, are obtained by evaporating a 

 olution containing equivalent proportions of the separate sulphate*. 

 The potuh salt contains ( Cu 0, SO, + KO, SO, + 6 Aq.) the ammonia 

 tlt ( Cu 0, SO, + I> H.O, SO, + 6 Aq.j, the soda salt (CuO, SO, + NaO, 

 80, + 2 Aq.) ; the latter is rather difficult to prepare. Double salts 

 may also be formed with the sulphates of several other metals. 



Ammo*io4lpliate of copper (CuO, SO, + 2 NH, + HO) separatee in 

 dark blue crystals on cautiously evaporating a solution of sulphate of 

 copper to which excess of ammonia has been added. Anhydrous sul- 

 phate of copper absorbs ammoniacal gas, yielding a compound con- 

 sisting of (2(CuO, SO,) + 5 NH,). 



JVrtrote o/ eo/yxr (CuO, NO, 6 Aq.). Prepared by dissolving copper 

 in nitric acid ; the following decomposition occurs : 



Co, + 4NO, = 3(CuO, 



Cupp<T. 



Nitric 

 acid. 



Nitrate of 

 copper. 



+ NO, 



Nitric 

 oside. 



By evaporation of the solution it is obtained in beautiful blue rhom- 

 boidal prisms. They rapidly deliquesce in the air, and are very soluble 

 in water or alcohol. 



Carbonate of copper is not known in the neutral state. Associated 

 with hydrated oxide it occurs native. [COPPEB, in NAT. HIST. Drv.] 

 When solutions of a salt of copper and an alkaline carbonate are mixed, 

 a bulky, gelatinous, green precipitate foils, usually having the com- 

 position (CuO, CO, + CuO, HO). Under various names it is used as a 

 pigment. [COLOURING HATTERS.] Mixed with lime and exposed to 

 the air its colour U changed to blue. 



Acetate of copper (CuO, C,H,0, + HO), verditer. Prepared by dig- 

 solving oxide or subacetate of copper in acetic acid and evaporating 

 the notation. It crystallises in oblique rhombic prisms, and is soluble 

 in five parts of boiling water. 



Subacetatet of copper. [ACETATE, Diacetate of Copper."] 



Artenite of copper (2CuO, AsO,) ; Scheele't green. Precipitated on 

 mixing solutions of arsenite of potash and sulphate of copper. It is exten- 

 sively used as a pigment. If acetate of copper be employed in the place 

 of sulphate the precipitate contains (CuO, C.H.,0., + 3(2CuO,AsO.,) ), 

 and is known as Schtninfurth green. The different arsenical greem, as 

 these pigments are called, owe their different tint* to the various 

 proportions of acetate and arsenite of copper contained in them, and 

 also occasionally to the presence of carbonate of copper. [COLOURING 

 MATTERS.) 



Protoxide of copper combines with many other acids, but the com- 

 pounds formed are comparatively unimportant. 



Hydrated protoxide of copper (CuO, HO) is precipitated when an 

 alkali is added to an aqueous solution of any copper salt. 



3 Binoride of copper (CuO,) ? is a brownish-yellow powder, formed on 

 treating hydrated protoxide of copper with peroxide of hydrogen. At 

 a slightly elevated temperature it loses one half of its oxygen. On 

 account of its liability to change it has been but little studied. 



4. Cupric acid 1 said to contain more oxygen than either of the lire- 

 ceding oxides, is supposed to be formed when finely divided copper, 

 caustic potash, and nitrate of potash ore together heated to redness. 

 Digested in water, the mass yields a blue solution that disengages 

 oxygen on being slightly warmed. 



Copper and liydroyen form 



ll'jilride of copper (Cu,H). 'It is obtained as a browu hydrate, 

 very unstable, when hypophosphorous acid is added to a solution of 

 sulphate of copper heated to 140 Fahr. 



Copper and nitrogen form 



\itridc of copper (Cu n N). Obtained on passing ammoniacnl gas over 

 oxide of copper heated in an oil-bath. 



Copper and lulfhur form two sulphides. 



' Dttulfhide of copper (Cu,S) is produced when copper is burnt in 

 vapour of sulphur. It melts more readily than metallic copper, and 

 forms a semi-crystalline mass on cooling. 



Protoutlphide of copper (CuS) is precipitated of a block colour \\lu-u 

 Mulpburetted hydrogen is jnased through a solution of a copper salt. 

 Washed and dried, it presents a very dark green ap)>eurance. 



Double tulpkidet of cooper and other mctobi are found native. 

 [COPPER, NAT. HIST. Drv.J 



Copper and chlorine form two chlorides, corresponding to the oxides 

 and sulphides. 



Dichi/ride of copper (Cu,Cl), Boyle's retnut cupri, is obtained hi 

 transparent tetrahedra on boiling the protochloride and metallic copper 

 together in close vessels. Heated it fuses and then volatilises. In 

 contact with air it quickly absorbs oxygen. It is but little soluble in 



water. Its aqueous solution is used in gas-analyses for the absorption 

 of carbonic oxide. 



ProtoeAloride of copper (C\iC\ + 1\,\.) is most easily formed 1 

 solving the oxide or carbonate in hydrochloric acid On evaji- 

 transparent, bright green, right-angled four aided prisms are obtained. 

 They are very deliquescent 



OryeM'iride* of copper, of variable composition, are obtained on 

 precipitating chloride of copper with a caustic alkali. 



Jtoxble Moride of copper and ammonium (CuCl, NH.C1 + 2Aq.) 

 crystallises on the cooling of a solution of the mixed chlorides in 

 equivalent proportions. 



CapraaimoniHia, in the state of diloriie, u by Graham and Kane 

 considered to be the true constitution of a compound containing 

 (H.NClCu), obtained on passing ammoniacal gas (MI.) over cliloridc 

 of copper heated to a temperature of about 400*. They regard this 

 salt as simply chloride of ammonium (NH.C1), in which one equivalent 

 of hydrogen is replaced by an equivalent of copper. 



Copper and iodine form only one compound, 



Diniodide of copper (Cu,I). A light brown powder, precipitated on 

 mixing together solutions of sulphate of copper, sulphate of iron, and 

 iodide of potassium 



J(CaO, 80,) + I(PeO, SO,) + KI = KO, SO, + Fe,O,, 380, + Cu,I 



Sulphate of Frotosulphatc Sulphate of Scaqutmilphate Diniodide 



copper. of iron. potuh. of iron. of copper 



Copper and bromine form two bromides, 



Dibromide of copper (Cu,Br) is produced when metallic copper is 

 heated in vapour of bromine. 



Protobrunudc of copper (CuBr) is obtained in crystals somewhat 

 resembling iodine in appearance, on evaporating in vocuo a solution of 

 hydrated protoxide of copper in aqueous hydrobromic acid. 



Cpper and cyanogen combine to form two simple cyanides, 



Diryanide of copper (Cu,Cy) falls as a white powder on adding 

 cyanide of potassium to a solution of dichloride of copper in a little 

 hydrochloric acid. It is soluble in ammonia, dilute acids, and alkaline 

 cyanides. 



Protocyanide of copper (CuCy). A brownish-yellow compound, pre- 

 cipitated on mixing solutions of sulphate of copper and cyanide of 

 potassium. It U very unstable. 



Double cyanide* of copper and other metals, or cuprocyaaida, arc 

 described under CVASOCFX. 



Alloys of copper. [ALLOY; BRASS; BRITANNIA METAL; BROXZE; 

 GERMAN SILVER.] 



Text* for the Sato of Copper. The most characteristic are the 

 following: Ammonia in excess forms a dork blue solution, ferro- 

 cyaaide of polonium yields a fine red-brown precipitate. A strip of 

 bright metallic iron, in a slightly acid solution of a copper salt, has, 

 after a short time, copper deposited on it with characteristic colour. 

 Before the blowpipe, on a charcoal support, copper compounds furnish 

 in the reducing flame, with carbonate of soda, a bead of metal 

 recognised as copper by its colour. 



Eii! million of Copper. In addition to the processes, for the quan- 

 titative determination of copper, mentioned at the commencement of 

 this article, the following volumetric method is recommended by 

 Mr. E. O Brown : Ten grains of the matter under examination ore 

 placed in a half-pint flask and dissolved in boiling diluted nitric acid ; 

 carbonate of soda is then added till a precipitate is formed, and lastly, 

 excess of acetic acid. About sixty grains of iodide of potassium arc 

 now introduced, and sufficient time having been allowed to elapse for 

 the crystals to dissolve, a standard solution of hyposulphate of soda is 

 poured in from a burette till the brown liquid assumes a yellow colour. 

 A little clear solution of starch is then added, and the addition of the 

 hyposulphite of soda continued until the blue iodide of starch has 

 entirely disappeared. ' 



In the above process core should lie taken that the iodide of 

 potassium is free from iodate of potash, and that the acetic acid 

 contains no sulphurous acid. The solution of starch should be dilute 

 and rendered clear by standing. The solution of hyposulphite of soda 

 is mode by dissolving 4000 grains of the salt in two gallons of water, 

 and standardising by means of electrotyped copper. 



COPPER, in a metallic state, produces no action on the human 

 system. When in the form of oxide its action is considerable, though 

 variable, being dependent on the kind and quantity of acid which it 

 may meet with in the stomach ; but all its Halts occasion peculiar 

 effects, which may be fatal if the dose be large. It is not necessary 

 that the substance should be introduced into the stomach, for the salts 

 of copper act in whatever way they are introduced into the system, 

 and the more energetically the more directly they enter the blood. 

 The greater the degree of solubility, the more rapidly are the formid- 

 able symptoms displayed. The chief preparations of copper used in 

 medicine ore, the sulphate, or blue vitriol, called also blue-stone ; thu 

 ammoniated sulphate or ammoniuret; and the diacetatc, or verdigris. 

 The two former arc usexl internally, the latter externally ; it and the 

 sulphate being applied by surgeons to wounds and sores in particular 

 states. 



Sulphate of copper influences powerfully the nervous system, and 

 acts as a tonic and onti^pasuiodic ; it has also some astriugn 



