Organic Nonmetallics

Show by means of a flow diagram or sketch how you would treat and dispose of the fly ash collected from a municipal incinerator. The fly ash contains toxic and nontoxic metals, nonmetallic inorganics, and organic halogen compounds. 

Ionic Inflate derivatives of nonmetallic elements such as selenium, sulfur, phosphorus, and iodine form an important class of reagents lor organic chemistry. Highly electrophilic phenylselenyl triflate can be used in the cyclization of 5- and 6-hydroxyalkenes, affording the corresponding tetrahydrofurans and pyrans [132] (equation 68). 

Appreciable interest was stirred by the sucessful use of nonmetallic catalysts such as oxides and organic metal complexes in electrochemical reactions. From 1968 on, work on the development of electrocatalysts on the basis of the mixed oxides of titanium and ruthenium led to the fabrication of active, low-wear electrodes for anodic chlorine evolution which under the designation dimensionally stable anodes (DSA) became a workhorse of the chlorine industry. 

Dislocations occur profusely in nonmetallic materials. As mentioned above, ceramics are brittle at ordinary temperatures, not because of a lack of dislocations but because these cannot easily glide due to strong bonding between the component atoms. Organic crystals, which are usually composed of molecules consisting of strongly bound atoms, linked by weak external bonds, usually glide by movement of molecules rather than atoms, and dislocations can be referred to the molecular array rather than the atom array. 

The facts noted in the four subsections of this chapter suggest that chemists ought to keep an open mind concerning the concept of chemical bonding. Useful as this concept is the field of organic chemistry, it becomes more and more meaningless and inadequate as we move toward inorganic, nonmetallic and, above all, metallic chemistry. 

In his x-ray work Mark showed a greater range of interests than the other investigators in the field. Mark and his collaborators studied elements, both metallic and nonmetallic, minerals, inorganic compounds, simple organic compounds, condensed gases, and macromolecular substances, and in addition they studied the physics of x-rays and of the diffraction phenomenon. 

An example (1S4) of the Overhauser effect in a nonmetallic system was afforded by diphenylpicrylhydrazyl (DPPH), an organic free radical. For partial saturation of the EPR of the radical, an approximately tenfold enhancement of the proton resonance from the ring protons of the DPPH molecule was observed. The Overhauser effect has also been observed in charcoals (proton resonance) and graphite (O resonance) 1S5), and natural crude oils (1S6). 

Dark reddish-brown liquid the only nonmetallic element that is a liquid at ambient temperatures strong disagreeable odor volatilizes density 3.12 g/mL at 20°C vapor density 7.59 g/L refractive index 1.6475 boils at 58.8°C solidifies at -7.2°C vapor pressure 64 torr at 0°C and 185 torr at 22°C critical temperature 315°C critical pressure 102 atm critical volume 127 cm /mol surface tension 39.8 dynes/cm at 25°C electrical resistivity 6.5 x 10i°ohm-cm at 25°C sparingly soluble in water (2.31 g/lOOg at 0°C and 3.35 g/lOOg at 25°C) soluble in common organic solvents. 

As Figure 6.8 shows, ionic compounds typically consist of elements found on opposite sides of the periodic table. Also, because of how the metals and nonmetals are organized in the periodic table, positive ions are generally derived from metallic elements and negative ions are generally derived from nonmetallic elements. 

The crux of organic mechanistic stereochemistry may be the Walden inversion, the inversion of stereochemistry about a four-coordinate carbon atom by nucleophilic attack of, for example, a hydroxide ion on an alkyl halide. Many reactions of inorganic molecules follow the same mechanism. In contrast, the dissociative mechanism of tertiary halides to form tertiary carbocatanion intermediates is essentially unknown among the nonmetallic elements silicon, germanium, phosphorus, etc. The reason for this is the generally lower stability of species with coordination numbers of less than 4, together with an increased stability of five-coordinate intermediates. This difference is attributable to the presence of d orbitals in the heavier elements (Chapter 18). 

---