Ammonia precipitation

Besides [Ni(CO)4] and organometallic compounds discussed in the next section, nickel is found in the formally zero oxidation state with ligands such as CN and phosphines. Reduction of K2[Ni (CN)4] with potassium in liquid ammonia precipitates yellow K4[Ni (CN)4], which is sensitive to aerial oxidation. Being... 

Nickel powder combines with carbon dioxide in ammonia solution forming nickel carbonate. Boiling the solution to expel ammonia precipitates pure carbonate, NiCOs. 

Pure selenic acid may be prepared from the solutions obtained in the foregoing processes by first neutralising with ammonia, precipitating barium selenate by the addition of barium chloride, and heating the separated precipitate with a solution containing the correct quantity of sulphuric acid. After removing the barium sulphate, a solution of pure selenic acid remains, and if this is concentrated as far as possible (see... 

TO 5 ml AgNO, SOLUTION, ADD AMMONIA. PRECIPITATE OF SILVER OXIDE DISSOLVES WHEN YOU ADD MORE AMMONIA. 

AgN03, white precipitate—Ag2C4H406, soluble in HN03, and ammonia. Precipitate dissolved in minimum quantity of ammonia, with addition of crystal of AgN03, deposits silver mirror on gently heating. 

E. Divers and T. Haga prepared monohydrated triammonium imidodisul-phonate, N(NH4)(NH4S03)2.H20, by the union of ammonia with diammonium imidosulphonate in the presence of water. The ammonia must be in excess or the salt will be decomposed. Cone. aq. ammonia precipitates this salt from a sat. soln. of the diammonium salt, or from a sat. soln. of the sodium salt, but in that case the precipitate is contaminated with the double sodium ammonium salt. Ammonia gas acts similarly and more effectively. The crystalline powder can be recrystallized by cooling a hot cone. soln. of ammonia in a closed vessel. The crystals resemble those of the potassium salt. The clear, lustrous crystals gradually effloresce and become opaque and damp and in a dry ammoniacal atm. over solid potassium hydroxide, the crystals slowly become opaque and anhydrous. WTien heated, the salt partly fuses and passes into the diammonium salt with the loss of both ammonia... 

It was noted that sodium hydroxide-precipitated catalysts were quite active in contrast with comparatively inactive ammonia-precipitated catalysts. Investigation of a series of catalysts with varying sodium content proved that the sodium content of a chromium oxide catalyst has a... 

A second portion of solution B is heated with NH4CI solution, yielding a white precipitate, Z>, nitrogen gas and ammonia. Precipitate D is soluble in HCi but does not react with H2S. 

Nickel Oithionate, NiS206.6H20, may be prepared by double decomposition of barium dithionate and nickel sulphate solutions.6 On concentration of the filtered solution, green triclinic prisms separate out. From its solution ammonia precipitates the hexammoniate, NiS206.6NH3. 

From the solution alkalies and ammonia precipitate the hydrated dioxide, whilst excess of ammonia yields osmium diammine hydroxide. Ferrous sulphate and alkali formates reduce the salt, liberating metallic osmium. 

Ammonia solution in the absence of ammonium salts small amounts of ammonia precipitate the basic salt as in reaction 1 ... 

Ammonium arsenates.—Excess of ammonia precipitates normal ammonium arsenate, (NH4)3As04, from concentrated solutions of the primary and secondary salts. It yields a very alkaline solution, decomposed by zinc and by aluminium with evolution of hydrogen and arsine.14 Secondary ammonium arsenate, (NH4)2HAs04, is gradually deposited from a concentrated solution of arsenic acid and ammonium hydroxide.15 Loss of ammonia, or addition of arsenic acid to its solution, converts it into primary ammonium arsenate, NH4H2As04, crystals of density 2-307 16 or 2-3105.17... 

Ammonia precipitates U(VI) as the sparingly soluble diuranate (NH4)2U207. Aluminium or Fe(III) can be used as a carrier [42]. In the presence of EDTA, only U, Ti, Be, Sn(IV), Sb, Nb, and Ta are precipitated by ammonia. Titanium is a suitable collector. Traces of uranium have also been co-precipitated as the phosphate with A1 as collector [64]. 

Morphine or Morphi This is the chief active principle of opium. The morphia of commerce is a white crystalline powder but when crystallized in alcohol, mnns brilliant, prismatic, transparent, and colorless crystals, which turn nitnc acid red. In powder, unlike strychnine, it is fusible without decomposition, and strongly decomposes iodic acid. It is insoluble iu ether, scarcely soluble iu water, and freely soluble in alcohol. Potassa and ammonia precipitate morphia from the solntions of its salts. 

From 1980 s, several research groups studied the components of EFE, independently [4,5,6]. Different purification methods were employed to isolate the enzymes, including sulfuric ammonia precipitation, gel filtration, ion exchanging, high-pressure liquid chromatography (HPLC)... 

Fig. 1. Differential thermal analysis of ammonia-precipitated chromic oxide gel-----, Air dried.----, Oven dried. 

Chromic oxide gel heated in air shows that the gel remains amorphous up to a temperature of 300°. At 350°, a very faint x-ray pattern is obtained. The gel heated to 400° shows a distinct pattern of crystalline chromic oxide. It has been reported that ammonia-precipitated gel crystallizes at 350° and the sodium hydroxide-precipitated gel crystallizes at 400°C 10). The gel heated in vacuum up to a temperature of 500° fails to show a clear pattern of crystalline Cr203, as may be expected from the results of D.T.A. 

Tin(IV) oxide gel was obtained by the ammonia precipitation method. Conversion to a stable sol-gel modification was effected by peptisation using choline. 

CaCOj CaO + CO2 Carbon dioxide is bubbled into a solution of sodium chloride saturated with ammonia, precipitating sodium hydrogencarbon-ate and leaving ammonium chloride in solution. The sodium hydrogencarbonate is then heated ... 

A particularly novel approach to lowering blood and brain ammonia concentrations in liver failure involves the use of 1-camitine and results of a recent study, following up on studies in experimental animals (Therrien et al, 1997) demonstrated a protective effect of L-camitine agonist ammonia-precipitated encephalopathy in cirrhotic patients (Malaguameia et al., 2005). 

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