Five Great Elements

The publication of the report Limits to Growth (4) by the Club of Rome had a major impact on thinking about the environmental impact of our cultural development. Under the assumption that the five basis elements of this study— population, the production of food, industrialization, pollution, and the use of nonrenewable resources—will keep increasing exponentially, they showed that, if unchanged, this would lead to enormous problems, as soon as the 21st century. The social consciousness of the problems caused by unlimited growth of these elements was greatly increased by this report by the Club of Rome. 

By 1830, fifty-five different elements were recognized, a long step from the four elements of ancient theory. In fact, the number was too great for the comfort of chemists. The elements varied widely in properties and there seemed little order about them. Why were there so many And how many more yet remained to be found Ten A hundred A thousand An infinite number ... 

Plutonium was the first element to be synthesized in weighable amounts (6,7). Technetium, discovered in 1937, was not isolated until 1946 and not named until 1947 (8). Since the discovery of plutonium in 1940, production has increased from submicrogram to metric ton quantities. Because of its great importance, more is known about plutonium and its chemistry than is known about many of the more common elements. The metallurgy and chemistry are complex. MetaUic plutonium exhibits seven aUotropic modifications. Five different oxidation states are known to exist in compounds and in solution. 

Unlike the di-f dihalides, such compounds differ little in energy from both the equivalent quantity of metal and trihalide, and from other combinations with a similar distribution of metal-metal and metal-halide bonding. So the reduced halide chemistry of the five elements shows considerable variety, and thermodynamics is ill-equipped to account for it. All four elements form di-iodides with strong metal-metal interaction, Prl2 occurring in five different crystalline forms. Lanthanum yields Lai, and for La, Ce and Pr there are hahdes M2X5 where X=Br or I. The rich variety of the chemistry of these tri-f compounds is greatly increased by the incorporahon of other elements that occupy interstitial positions in the lanthanide metal clusters [3 b, 21, 22]. 

The discussion of the activation of bonds containing a group 15 element is continued in chapter five. D.K. Wicht and D.S. Glueck discuss the addition of phosphines, R2P-H, phosphites, (R0)2P(=0)H, and phosphine oxides R2P(=0)H to unsaturated substrates. Although the addition of P-H bonds can be sometimes achieved directly, the transition metal-catalyzed reaction is usually faster and may proceed with a different stereochemistry. As in hydrosilylations, palladium and platinum complexes are frequently employed as catalyst precursors for P-H additions to unsaturated hydrocarbons, but (chiral) lanthanide complexes were used with great success for the (enantioselective) addition to heteropolar double bond systems, such as aldehydes and imines whereby pharmaceutically valuable a-hydroxy or a-amino phosphonates were obtained efficiently. 

Of much greater significance than this, however, was Mme. Curie s observation that the activity of the uranium mineral pitchblende is four or five times as great as one might expect it to be from its uranium content (24). She concluded that the ore must contain another radioactive element in addition to uranium, and that, since the composition of the ore was known, the active element must be present in extremely small amount and must therefore be very active indeed. Therefore it became necessary to work up large quantities of pitchblende and to make elaborate and tedious fractionations of this complex ore. 

Hermetis saith It is a single Numen, a divine, wondrous, and holy office, while it encloseththe whole world within it, and will become true with all else, and truly overcometh the elements and the five substances. Eye hath not seen, nor hath ear heard, neither have entered the heart of any man, how the heaven hath naturally embodied to truth of this Spirit, in it the truth doth stand alone, therefore it is called the voice of truth. To this power Adam and the other patriarchs, Abraham, Isaac, and Jacob, owed their bodily health, their long life, and finally prospered in great wealth thereby. 

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