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The brown to black coloured mainly amorphous polymers obtained in high yield (<95%) are often soluble in polar solvents. In one case molecular wei ts of 19000 were observed by light scattering ... 

Verdin icterus is deemed to be the prototyp>e of obstructive jaundice, particularly in long-standing courses of the disease melas icterus displays a greyish green hue rubin icterus (rust-coloured) is mainly seen as a sign of hepatocellular jaundice, whereas flavine icterus is more likely to occur in cases of haemolysis (Th. Brugsch, 1930). Such systematization of the icteric forms in terms of pathogenesis is unreliable and obsolete, since the differences in colour mainly correlate with the duration of the jaundice and the level of serum bilirubin. 

Carbon dioxide-enriched atmospheres (10-20% CO2 in air) are used to extend the postharvest life of strawberries [162]. However, some adverse effects on colour, mainly a reduction in the intensity of red of the internal tissue, have been reported. Changes in strawberry anthocyanins and other polyphenols in response to carbon dioxide treatments have been studied [36]. The external and internal anthocyanin contents were significantly different in fruit stored in air compared with the initial values or with those of fruit stored under CO2 enriched atmosphere. No differences in the external anthocyanin content between fruit stored under C02-enriched atmospheres and freshly picked fruit were observed. However, there was a noticeable decrease in the internal anthocyanin content, particularly at 20... 

Figure 41.9. Left Animation of the new British Antarctic Survey Research Station Halley VI. The red coloured main module contains 72 research station at night.

Potatoes are tubers in which starch is stored and, depending mainly on the variety, they vary in shape (e g. round, oval, kidney, irregular) skin eolour (mainly cream and/or red) flesh colour (mainly cream or lemon) and depth of eyes (where sprouts develop). 

Covers all land eastwards to the Urals, southwards to North Africa and up to Syria, Iraq and Iran. Scale - 1 5,500,000, 4-colour artwork. Features main roads, railways, oil and gas pipelines, plus extra information including national flags, currencies and populations. 

Among the metals, for example, sodium and potassium are similar to each other and form similar compounds. Copper and iron are also metals having similar chemical properties but these metals are clearly different from sodium and potassium—the latter being soft metals forming mainly colourless compounds, whilst copper and iron are hard metals and form mainly coloured compounds. 

This is the most common and stable state of chromium in aqueous solution. The Cr ion, with 2d electrons, forms mainly octahedral complexes [CrX ], which are usually coloured, and are kweticallv inert, i.e. the rate of substitution of X by another hgand is very slow consequently a large number of such complexes have been isolated (see below, under chromium(III) chloride). 

Phenol condenses with phthahc anhydride in the presence of concentrated sulphuric acid or anhydrous zinc chloride to yield the colourless phenolphthalein as the main product. When dilute caustic alkah is added to an alcoholic solution of phenolphthalein, an intense red colouration is produced. The alkali opens the lactone ring in phenolphthalein and forms a salt at one phenolic group. The reaction may be represented in steps, with the formation of a h3q)othetical unstable Intermediate that changes to a coloured ion. The colour is probably due to resonance which places the negative charge on either of the two equivalent oxygen atoms. With excess of concentrated caustic alkali, the first red colour disappears this is due to the production of the carbinol and attendant salt formation, rendering resonance impossible. The various reactions may be represented as follows ... 

Hexafluorobenzene [392-56-3] M 186.1, m 5.1°, b 79-80°, d 1.61, n 1.378. Main impurities are incompletely fluorinated benzenes. Purified by standing in contact with oleum for 4h at room temperature, repeating until the oleum does not become coloured. Washed several times with water, then dried with P2O5. Final purification was by repeated fractional crystn. 

The bitumens have a good order of chemical corrosion resistance, have reasonably good electrical insulation properties and are very cheap. Their main disadvantages are their black colour and their somewhat brittle nature. 

This leaction is lesorted to for the reason that naphthalene forms only the n-nitro-compound with niti icacid. The method, similar to that used for prepaiing aniline from nitiobenzene, cannot, therefore, be employed for the production of /3-n.tphtliyl-.amine. u-Naphthol is mainly used foi the manufacture of yellow and orange colours (Martins and naphthol yellow) by the action of nitric acid, and are similai m constitution to picric acid (see Prep. 107). 

Sulfur forms two main series of oxohalides, the thionyl dihalides OS X2 and the sulfuryl dihalides 02S X2. In addition, various other oxofluorides and peroxofluorides are known (p. 688). Thionyl fluorides and chlorides are colourless volatile liquids (Table 15.14) OSBt2 is rather less volatile and is orange-coloured. 

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