Metal or Nonmetal

Impurities in cmde metal can occur as other metals or nonmetals, either dissolved or in some occluded form. Normally, impurities are detrimental, making the metal less useful and less valuable. Sometimes, as in the case of copper, extremely small impurity concentrations, eg, arsenic, can impart a harmful effect on a given physical property, eg, electrical conductivity. On the other hand, impurities may have commercial value. For example, gold, silver, platinum, and palladium, associated with copper, each has value. In the latter situation, the purity of the metal is usually improved by some refining technique, thereby achieving some value-added and by-product credit. 

The effect of impurities in either structural material or corrosive material is so marked (while at the same time it may be either accelerating or decelerating) that for rehable results the actual materials which it is proposed to use should be tested and not types of these materials. In other words, it is much more desirable to test the actual plant solution and the actual metal or nonmetal than to rely upon a duphcation of either. Since as little as 0.01 percent of certain organic compounds will reduce the rate of solution of steel in sulfuric acid 99.5 percent and 0.05 percent bismuth in lead will increase the rate of corrosion over 1000 percent under certain conditions, it can be seen how difficult it would be to attempt to duplicate here all the significant constituents. 

Along the stairway (zig-zag line) in the periodic table are several elements that are difficult to classify exclusively as metals or nonmetals. They have properties between those of elements in the two classes. In particular, their electrical conductivities are intermediate between those of metals and nonmetals. The six elements... 

The (compositionally) simplest mineral class comprises the native elements, that is, those elements, either metals or nonmetals that occur naturally in the native state, uncombined with others. Native gold, silver, and copper, for example, are metals that naturally occur in a ductile and malleable condition, while carbon - in the form of either graphite or diamond -and sulfur are examples of nonmetallic native elements. Next in compositional complexity are the binary minerals composed of two elements a metal or nonmetallic element combined with oxygen in the oxides, with a halogen - either fluorine, chlorine bromine, or iodine - in the halides, or sulfur, in the sulfides. The oxide minerals, for example, are solids that occur either in a somewhat hard, dense, and compact form in mineral ores and in rocks, or as relatively soft, unconsolidated sediments that melt at moderate to... 

A convenient way of displaying the elements is in the form of a periodic table, such as is shown on page 372 of this book. The basis for the arrangement of the elements in the periodic table will be discussed at length in Chap. 3. For the present, the periodic table will be regarded as a convenient source of general information about the elements. It will be used repeatedly throughout the book. One example of its use, shown in Fig. 1-1, is to classify the elements as metals or nonmetals. All the... 

Nitrogen has many uses. It is the second most commonly produced chemical in the United States. Its chemical and physical properties, along with the five electrons in its outer shell, make it a versatile element that can react as a metal or nonmetal to produce numerous compounds. Some of its uses are based on its inertness as a gas (N ) and its ability to be liquefied to provide very low temperatures. 

It is tnc thai ionic compountb such as [NH ) [B(C6Hsh] are known in which there are no extremfy adjve metals or nonmetals. Nevertheless, the above statement b for afl practical purposes correct, and we can consider compounds such as ammonium trtrajrfienylbornle to result from the particular covalent bonding properties of nitrogen and boron. 

The fixation of C02 by amines, which has been recognized for a long time, can either take place directly or it can be mediated by metal or nonmetal species to provide a carbamate group, RR NC02 , which is bound either ionic or covalently to an electrophilic center [1-5]. The direct interaction of C02 with primary or secondary amines can afford carbamic acids or alkylammonium carbamates (Equations 6.1 and 6.2) [1, 2], In the presence of metals, metal salts (Equation 6.3) [3j, k] or metal-complexes, metal carbamates can be obtained [3, 4] ... 

In accounts of descriptive inorganic chemistry - especially in more elementary texts - it is common practice to classify elements as metals or nonmetals , with semi-metals or metalloids as a borderline case, according to the nature of the elemental substance. The chemistry of an element is, to some extent, broadly predictable from this classification. Metallic elements tend to form ionic oxides and halides they form... 

Ammonium Salts, Metals, or Nonmetals, or Sulfides. Mixtures with ammonium salts, powdered metals, phosphorus, silicon, sulfur, or sulfides are readily ignited and potentially explosive.4... 

In general, would you expect metals or nonmetals to have higher electronegativity ... 

Interpolation may be defined as the presence of an ion, metal or nonmetal, in positions formed by a host structure of fixed composition which may otherwise... 

Alloys are materials composed primarily of one metal, called the parent metal, doctored with smaller amounts of other metals or nonmetals. When tin or arsenic is added to copper, the metal becomes harder, stronger, and easier to cast. This metallic mixture is known as bronze, and its discovery ushered in a whole new suite of tools, weapons, armor, and decorative objects. So dramatic was the change from the copper and stone implements that preceded it, that bronze became the defining feature of the period, now known as the Bronze Age. Alloys such as bronze have played and continue to play a huge role in building the modern world. 

Subsequent to Stock s work, many additional hydrides have been prepared and characterized, including a number by R. Schaeffer and associates, and today about 35 neutral binary boranes (including isomers) are known (Table 5-2). Many derivatives containing organic or halo substituents have been synthesized, and thousands of other species have been generated via insertion of metal or nonmetal heteroatoms into borane frameworks as described in Section 5-6. The polyhedral borane anions (see below) add yet another dimension to the remarkably rich area of polybo-rane chemistry. 

Practice Problem 1.12 Classify each of the following as metal or nonmetal ... 

Ofiier main gronp metals (or nonmetals) also serve as the agents for transfer of organic units to Pd for the Heck reaction these include lead, lithium, magnesium, sodium, and boronic acids. ... 

---