Insoluble copper carbonate

The social analogy can be extended again. Dissolution is the opposite of precipitation, and in the complete absence of water, all unions of salts are solid. Water, however, can be a home wrecker. When a salt is wet, the molecules of water can insinuate themselves between ions. Table salt, sodium chloride, is solid enough in the shaker, but when it is wet, the molecules of water work their way between the chloride ion and sodium ion and keep them apart. Why doesn t water come between the carbonate ion and the copper ion in the insoluble copper carbonate of the earlier demonstration It boils down to a trade-off if the divorce is more costly than any possible benefit, the union stays solid. If not, let the proceedings begin. 

It is a reddish-brown solid, insoluble in carbon disulphide. It dissolves in carbon tetrachloride on heating, from which solution it crystallises out in black needles on cooling.4 It is decomposed by heat and bums, leaving a residue of selenium. It combines with the selenides of certain metals, e.g. copper and silver, forming double selenides.5... 

BASIC SALT. A compound belonging to the categories of both salts and bases, because it contains OH (hydroxyl) or O (oxide) as well as the usual positive and negative radicals of normal salts. Among the best examples are bismuth subnitrate, often written BiONO, and basic copper carbonate, Cu2 (OH)2CO.). Most basic salts arc insoluble in water and many arc of vaiiable composition. 

Copper Carbonate (Basic), CuCOi CutOH j. dark-green monoclinic crystals, insoluble in cold HiO decomposes in hot H 0, soluble in potassium cyanide. Malachite, a copper ore. is of this composition. Refined compound is used as a pigment. 

Selenic Acid.—Selenic Acid, H2Se04, is also a il colourless syrupy liquid it can be produced by direct oxidation of selenium by chlorine water, but on concentra-I tion the resulting hydrochloric acid reduces the selenic acid I to selenious acid, as hydriodic acid reduces sulphuric acid. It is best prepared by addition of copper carbonate to the mixture of selenic and hydrochloric acids obtained in that way selenate and chloride of copper are formed the 1 mixture is evaporated to dryness, and the copper chloride is dissolved out with alcohol, leaving the insoluble selenate 1 behind. The selenate is dissolved in water, and on treatment with sulphuretted hydrogen, copper sulphide is precipitated, and removed by filtration the selenic acid is then concentrated if it contains a trace of water, it is a heavy liquid 5 but if quite anhydrous, it forms a solid, melting at 58°. 

Cuprous carbonate.—Carles9 claims to have prepared cuprous carbonate as a glaucous green powder, insoluble in water, by the action of copper on copper carbonate in presence of liquefied ammonia. 

Very little information is available concerning the thermal stability of the metallic salts of the acid carbonates and thiocarbonates. Calcium glyc-eritol dicarbonate [C3H60H(C0s )2Ca ], although very unstable in solution, could be stored at room temperature in an anhydrous state for a short period of time. On being strongly heated it charred, with the evolution of acrolein. A hydrated 0-(sodium thiocarbonyl) derivative of cellulose became insoluble in alkali within 24 hours at room temperature, due to decomposition. On the other hand, many metal xanthates, particularly the insoluble copper salts, which are readily obtained in a pure, anhydrous state, appear to be reasonably stable at about 20°. This very limited evi-... 

When potassium ferricyanide is warmed with a solution of bleaching powder to 70° C. a considerable evolution of gas takes place, and a reddish deposit of ferric oxide and calcium carbonate is formed. The filtered solution is concentrated and the potassium nitroprusside extracted with alcohol, and converted into the insoluble copper salt by addition of cupric chloride. This latter is decomposed with sodium hydroxide, yielding the sodium salt, which may be further purified by dissolving in a little water, addition of alcohol, and subsequent evaporation after filtering off any insoluble material.2 The constitution to be assigned to sodium nitroprusside in particular, and hence to nitro-prussides in general, has been a subject of debate, Browning s3 formula is —... 

It has been mentioned in Section 4.1 that cupric chloride causes chlorination reactions. Thus, chlorinated aldehydes (see Eq. (9.26)) are the main by-products. Others include acetic acid and chlorinated acetic acids. Light ends are carbon dioxide, methyl, and ethyl chloride. By chlorination, oxidative, and hydrolytic reactions, oxalic acid is formed causing insoluble copper oxalate. In order to avoid an accumulation in the catalyst, it is continuously thermally decomposed by heating a small side stream in the regeneration step (reactor (i) in the one-stage, reactor (m)... 

Cupric oxide or black copper oxide.) CuO. Mol. wt. 79.54 sp. gr. 6.4 decomposes at 1026°C. Insoluble in water and soluble in acids and NH4CI. Derived by the ignition of copper carbonate or copper nitrate, copper hydrate, or oxidation of lower oxides. 

A flow diagram for the system is shown in Figure 5. Feed gas is dried, and ammonia and sulfur compounds are removed to prevent the irreversible buildup of insoluble salts in the system. Water and soHds formed by trace ammonia and sulfur compounds are removed in the solvent maintenance section (96). The pretreated carbon monoxide feed gas enters the absorber where it is selectively absorbed by a countercurrent flow of solvent to form a carbon monoxide complex with the active copper salt. The carbon monoxide-rich solution flows from the bottom of the absorber to a flash vessel where physically absorbed gas species such as hydrogen, nitrogen, and methane are removed. The solution is then sent to the stripper where the carbon monoxide is released from the complex by heating and pressure reduction to about 0.15 MPa (1.5 atm). The solvent is stripped of residual carbon monoxide, heat-exchanged with the stripper feed, and pumped to the top of the absorber to complete the cycle. 

Copper(II) oxide is insoluble in water, but readily dissolves in mineral acid or in hot formic or acetic acids. CuO slowly dissolves in ammonia solution, but alkaline ammonium carbonate solubilizes it quickly. 

There are four basic sulfates that can be identified by potentiometric titration using sodium carbonate (39,40) langite [1318-78-17, CuSO -3Cu(OH)2 H2 i brochantite [12068-81 -4] CuSO -3Cu(OH)2 antedite [12019-54-4] CuSO -2Cu(OH)2 and CuS0 -Cu0-2Cu(0H)2-xH20. The basic copper(II) sulfate that is available commercially is known as the tribasic copper sulfate [12068-81 ] CuS04-3Cu(0H)2, which occurs as the green monoclinic mineral brochantite. This material is essentially insoluble in water, but dissolves readily in cold dilute mineral acids, warm acetic acid, and ammonia solutions. 

Bromo-2 -(3"-dimethylaminopropyl)-amino4 potassium carbonate (5 g) and copper powder (0.4 g). It is then heated under reflux for 4B hours, cooled, and the insoluble matter filtered off. After washing with dimethylformamide (20 cc), the filtrate is taken up in distilled water (200 cc). The base formed is extracted with ether (3 times with 50 cc), the ethereal solution is dried over sodium sulfate, the ether driven off on a water-bath and the residue distilled. In this way there is obtained 3ethereal hydrogen chloride on the base dissolved in acetone this hydrochloride melts at 180°C. 

For some non-ferrous metals (copper, lead, nickel) the attack by sulphuric acid is probably direct with the formation of sulphates. Lead sulphate is barely soluble and gives good protection. Nickel and copper sulphates are deliquescent but are gradually converted (if not leached away) into insoluble basic sulphates, e.g. Cu Cu(OH)2)3SO4, and the metals are thus protected after a period of active corrosion. For zinc and cadmium the sulphur acids probably act by dissolution of the protective basic carbonate film. This reforms, consuming metal in the process, redissolves, and so on. Zinc and cadmium sulphates are formed in polluted winter conditions whereas in the purer atmospheres of the summer the corrosion products include considerable amounts of oxide and basic carbonate. ... 

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