Potassium nickelate

With substances that give up an electron more readily than aromatic hydrocarbons, such as potassium, nickel carbonyl, cyanide ion, or iodide ion, complete transfer of an electron occurs and the TCNE anion radical is formed (11). Potassium iodide is a particulady usefiil reagent for this purpose, and merely dissolving potassium iodide in an acetonitrile solution of TCNE causes the potassium salt of the anion radical to precipitate as bronze-colored crystals. 

Isomerism of the but-3-enoic acids into the E-but-2-enoic acids is base-catalysed (Table 8.8), whereas the formation of the other isomers indicates the participation of rt-allylnickel complexes in the reaction. Potassium nickel tetracarbonyl is a considerably poorer catalyst, compared with nickel cyanide, whereas nickel sulphate and nickel iodide are ineffective catalysts. 

Potassium nickel ferricyanide [potassium nickel hexakis(cyano-ferrate(3-))] KNi[Fe(CN)6] [53295-14-0]... 

Nickel oxide combines with sodium or potassium hydroxide at elevated temperatures (>700°C), forming sodium or potassium nickelate i.e., K2Ni02 ... 

Nickel potassium sulphate see potassium nickel sulphate. 

Similar pairs of isomers of compounds of nickel as well as of palladium and of platinum with other groups have also been obtained.8 The x-ray study of crystalline potassium nickel dithio-oxalate9 has shown it to be isomorphous with the palladium and platinum compounds and has provided a detailed verification of the planar structure... 

W. C. Ball and H. H. Abram added 10 c.c. of bismuth nitrate soln. to 40 c.c. of a 50 per cent. soln. of sodium nitrite, and then a soln. of 5 grms. of ammonium nitrate and 2 grms. of nickel nitrate in 20 c.c. of water—all cooled to 0°—in a few minutes a yellowish-brown, microcrystalline powder of ammonium nickel nitrito-bismuthite was formed. The composition of different specimens varied considerably, and the salt slowly decomposes it is quickly hydrolyzed by water. In an analogous manner, potassium nickel nitritobismuthite, K4NiBi2(N03)12.6H20, was formed as an unstable, yellowish-brown, microcrystalline powder similarly... 

Potassium nickel (IV) paraperiodate J-hydrate, 6 201, 202 analysis of, 5 203 Potassium nitridoosmate(VIII), 6 204... 

Double Chromates.—Several double chromates containing nickel have been prepared. Amongst these are potassium nickel chromate,3 K2Cr04.NiCr04.6H20, and the corresponding ammonium, rubidium, and ccesium salts. Basic chromates have also been described.4... 

Nickel Azoimide, Ni(N3)2.H20, and a Basic Azoimide, N3.Ni.OH, have been obtained11 as green explosive crystalline bodies, exploding at 247—271° C. Bright green, explosive Potassium Nickel Azoimide, KN3.Ni(N3)2, has also been prepared. 

Puschel and Stefanac ° use alkaline hydrogen peroxide in the oxygen flask method to oxidize arsenic to arsenate. The arsenate is titrated directly with standard lead nitrate solution with 4-(2-pyridylazo) resorcinol or 8-hydroxy-7-(4-sulpho-l-naphthylazo) quino-line-5-sulphonic acid as indicator. Phosphorus interferes in this method. The precision at the 99% confidence limit is within 0.67% for a 3-mg sample. In another variation, Stefanac used sodium acetate as the absorbing liquid, and arsenite and arsenate are precipitated with silver nitrate. The precipitate is dissolved in potassium nickel cyanide (K2Ni(CN)4) solution and the displaced nickel is titrated with EDTA solution, with murexide as indicator. The average error is within + 0.19% for a 3-mg sample. Halogens and phosphate interfere in the procedure. 

Potassium nickel sulfate (6H2O) [13842-46-1] M 437.1. Crystd from H20(1.7mL/g) between 75 ... 

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