Tetra, black

Some direct dyes are sensitive to reduction or hydrolysis under alkaline conditions, particularly if temperatures above 100 °C are used (section 3.1.3) pH 6 is frequently favoured for stability and this can usually be achieved using ammonium sulphate. A few dyes give optimal results under alkaline conditions, using sodium carbonate or soap the tetra-amino dye Cl Direct Black 22 (12.22) is an example. Whether or not an addition is needed will depend on whether alkali is already present in the commercial brand. 

Fel3, first isolated in the pure state as recently as 1988 as a black, fairly stable solid (though unstable in solution), reacts with iodide to give the previously characterized complex [Fel4]. Iodide appears stable coordinated to iron(III) in ternary porphyrin complexes such as (12,17-diethoxycarbonyl-2,3,6,7,ll,18-hexamethylcorrphycenato)-iodo-iron(III), where Fe — I = 2.600 A, though it is oxidized by the mono-oxidized form of /.t-oxo-di-iron(III) bis-tetra-phenylporphyrin. " Remarkably, iodide has been reported coordinated to iron(V), in [Fe(313)I]. ... 

Isomeric with the series are the black dodecammino-hexol-tetra-cobaltic salts, [Co(OH)6(Co(NH3)4)3]R6, which may be regarded as polymers of the hexammino-triol-dicobaltic salts. 

Tetra-iodo-diammino-platinum, [Pt(NH3)2I4], is obtained as an amorphous black powder when an alcoholic solution of iodine is mixed with traw-di-iodo-diammino-platinum. 

When irradiating a 1 1 blend of polychloroprene and poly (butadiene-acrylonitrile) (NBR) reinforced by 50 phr furnace black and containing 5-15 phr of tetra methacrylate of bisglycerol phthalate, it exhibited a tensile strength of 20 MPa (2900 psi) at a dose of 15 Mrad (150 kGy) with values of elongation at break in the range 420 to 480%. These values are equal to or better than those obtained from similar compounds cured chemically.199... 

The tetra-iodide forms small, brilliant, black crystals, having a density of 5-05 at 15° C. When heated above 100° C. it dissociates into tellurium and iodine. When dissolved in excess of iodine it appeal s probable that part of the iodide is in a bimolecular condition.6 It is unattacked by moist air, but is slowly decomposed by cold water, and on warming, hydrolysis occurs with the formation of an oxy-iodide of uncertain composition on boiling with water complete hydrolysis to hydrogen iodide is effected 7... 

Analogous with the tetrachloride and tetrabromide, additive compounds are formed by the tetra-iodide with the alkali iodides. The telluri-iodides,9 of the general formula XaTeIe, are black, crystalline substances, which, like the tellurichlorides and telluribromides, generally crystallise in the regular system when anhydrous. They are decomposed... 

Fig. 11.4 Cavity in the tetra (iso-amyl)ammonium fluoride hydrate. Host water molecules are represented as black dots linked by hydrogen bonds. Fluoride anion is incorporated into this framework (exact position remains unknown). Tetra(iso-amyl)ammonium cation is included in the cavity, its atoms are given by thermal ellipsoids (ORTEP plot)...

The bicyclic octadentate (89) forms Ni2L in which the ligand has lost the four imino hydrogens.481 A novel reaction occurs when an aqueous solution of 11.13-dimethyl-1,4,7,10-tetra-azacyclotrideca-10,12-dienenickel(n) iodide is allowed to stand at pH 1. Black crystals separate and X-ray analysis shows them to contain a new octadentate bicyclic macrocycle formed by the linking of two monomeric macrocycles through the methine carbons. The nickel(n) is in a square-pyramidal N4I environment.482... 

Kornienko et al. [32] have utilized wetproofed electrodes of acetylene black containing 40 wt.% PTFE to reduce CFC 113 to CTFE in 3 M LiCl at 35°C. The presence of tetraalkylammonium cations considerably facilitates the reduction process. It is assumed that CFC 113, like other halogenated compounds, forms a positively charged complex with the tetraalkylammonium cation, which is much more easily reduced than the CFC 113 itself. The largest effect was found for tetra-M-butylammonium ion (TBA+), giving a 96% yield of CTFE. The increase in CTFE current yield is explained by the shift of potential to less cathodic values and to the displacement of water molecules by organic cations in the layer next to the electrode because hydrogen evolution is slower. 

Iridium Tetra-iodide, Irl4, results when a solution of ammonium chloriridate or of iridium chloride in hydrochloric acid is boiled with potassium iodide.4 It is precipitated as a black, insoluble powder, which decomposes at 100° C. 

As prepared by the foregoing method, however, platinum di-iodide is obtained as a black, insoluble powder, stable in air. It is slowly soluble in hydriodic acid, but the solution undergoes decomposition into the tetra-iodide and metallic platinum. When heated to about 300° or 850° C. it dissociates into its components. 

Iodo-platinic Acid, HaPtI6.9HaO.—This add exists in solution when platinum tetra-iodide is dissolved in aqueous hydriodic add. Upon concentration it separates out in reddish black, monoclinic crystals. These are easily soluble in water they deliquesce upon exposure to air, whilst in vacuo they lose hydrogen iodide. When heated to 100° C. platinum tetra-iodide is obtained. 

Ammonium Iodo-platinate, (NH4)sPtI6, crystallises in cubo-octa-hedra haying a black colour and a metallic lustre. The solution is unstable, a deposit of platinum tetra-iodide being obtained on standing.1... 

On a spot plate, mix a drop of the test solution, one drop lead nitrate, 1 drop potassium cyanide (POISON), and 2 drops freshly prepared sodium tetra-hydroxostannate(II) reagent. A brown to black colouration (precipitate) is characteristic for bismuth. 

Fig. 7.5 The distribution of all E2P2 complex C7stal contacts visualized on the E2P2 tetra-mer. The ecotin dimer is colored medium grey, the serine proteases are colored light grey and the costal contact loops are colored black. The catalytic triad of the protease is co-...

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