Red and Orange

In order that the rate of cure of phenolic moulding compositions is sufficiently rapid to be economically attractive, curing is carried out at a temperature which leads to the formation of quinone methides and their derivatives which impart a dark colour to the resin. Thus the range of pigments available is limited to blacks, browns and relatively dark blues, greens, reds and oranges. 

FIGURE 3.26 When two 1s-orbitals overlap in the same region of space in such a way that their wavefunctions have opposite signs, the wavefunctions (red and orange lines) interfere destructively and give rise to a region of diminished amplitude and a node between the two nuclei (blue line). 

CD-R was something of a surprise invention as, in the late 1980s, most of the major manufacturers in the optical memory area were commercializing the non-standard and relatively expensive WORM media, while focusing their research and development efforts on erasable optical storage. It was also believed that a writeable CD-Audio/CD-ROM-compatible medium was not feasible, due to the high reflectivity needed to meet the CD standard as defined by the Red and Orange Books.196... 

The red and orange forms of RhCl[P(C6H5)3]3 have apparently identical chemical properties the difference is presumably due to different crystalline forms, and possibly bonding in the solid. The complex is soluble in chloroform and methylene chloride (dichloromethane) to about 20 g./l. at 25°. The solubility in benzene or toluene is about 2 g./l. at 25° but is very much lower in acetic acid, acetone, and other ketones, methanol, and lower aliphatic alcohols. In paraffins and cyclohexane, the complex is virtually insoluble. Donor solvents such as pyridine, dimethyl sulfoxide, or acetonitrile dissolve the complex with reaction, initially to give complexes of the type RhCl[P(C6H6)3]2L, but further reaction with displacement of phosphine may occur. 

The dimeric complex [RhClL2 L>, present in varying amounts according to the conditions, is also an effective catalyst via a similar hydride route involving complex 1. An originally proposed (80) dimeric tetrahydride was not detected. Detailed crystal structures of both the red and orange forms of RhCl(PPh3)3 have appeared (81). 

In the pure state m- and p-nitrophenols are colourless, but the o-com-pound, on the other hand, is yellow. The salts of all three, however, are intensely coloured, the o- and wi-compounds being orange-red and orange-yellow and the p-compound deep yellow. (Use of p-nitro-phenol as an indicator.)... 

Dichlorobenzidine is used primarily in the production of yellow, and some red and orange pigments for the printing ink, textile, paper, paint, rubber, plastic, and related industries (EPA 1979a). As of 1983,... 

Light is scattered all around us— the fact that the sky above us appears blue, the clouds white, and the sunset shades of reds and oranges is a consequence of preferential scattering of light from air molecules, water droplets, and dust particles. This scattered light carries messages about the scattering objects. 

The SrCl molecule emits a series of bands in the 620-640 manometer region - the "deep red" portion of the visible spectrum. Other peaks are observed. Strontium monohydroxide, SrOH, is another substantial emitter in the red and orange-red regions [1,11]. The emission spectmm of a red flare is shown in Figure 7.1. 

Anthocyanins are flavonoid compounds that are widely distributed in plants. They are responsible for blue, purple, violet, magenta, red, and orange plant coloration (Jackman and Smith, 1996). The range of colors associated with anthocyanins results from distinct and varied substitution of the parent C6C3C6 (agly-cone) nucleus (Figure FI.1.2), in addition to acylation patterns and various environmental influences (Jackman and Smith, 1992). 

The plant grow-light contains more violet, indigo, and blue waves and may not contain yellow, red and orange waves. Plants need shorter wavelength waves of energy for photosynthesis to take place. 

These common uses only hint at all the things that transition metals can do. The copper penny, for instance, is mostly made of zinc, another transition metal. Chromium provides the shiny, mirror-like metal coating on chrome car bumpers, but is also added to some lasers to make their light shine red. Nickel and chromium combine in an alloy that can be coiled into the wires that heat toasters and hair dryers. Titanium dioxide is a very white reflective compound used in toothpaste and paints. The transition metal cadmium is used in brilliant and permanent colors such as cadmium yellow, red, and orange. Artists have used cadmium-based paints for hundreds of years, and manufacturers used the colors more recently in plastic products. However, the colors are rarely used now that scientists have discovered that cadmium pollution can cause cancer and other health problems. 

Indeed, the 17-electron radicals in Eq. (43) with M = Mo and W can both be readily collected as red and orange crystals merely when the ion-pair annihilation is carried out in acetonitrile solutions. 

Carry fat-soluble vitamins and natural color compounds, for example, yellow pigments to improve the color of egg yolks red and orange colors for feeding salmon. 

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