Boron
Boron is a metalloid element which has the atomic number 5, an average atomic weight of 10.81, and is designated by the atomic symbol B. It has a melting point of 3767 ° F (2075 ° C) and boils at about 7232 ° F(4000 ° C).
Although boron was discovered nearly 200 years ago, scientists have not yet thoroughly explored all of its properties. Pure boron does not exist in nature, and the impurities present in many samples have made it difficult to characterize the element. But it is known that boron crystals are harder than any other substance except diamond, and boron compounds have been put to a variety of uses, from building jet planes to washing clothes.
The story of boron's discovery has its roots in the uneasy political relations between France and England in the early 1800s. Scientific discoveries in England, especially by the pioneering chemist Sir Humphry Davy, made France's emperor Napoleon (1769-1821) jealous. Davy had achieved astonishing results in discovering new elements, such as sodium and potassium, by using electricity to split compounds. At the time, the electric battery had just been invented, and scientists were rushing into the new field of electrochemistry. In the name of French nationalism, Napoleon funded construction of a bigger, more powerful battery for similar experiments to be conducted by French chemists Joseph Gay-Lussac and Louis Thenard. But as it turned out, the battery was not needed. Gay-Lussac and Thenard were able to duplicate Davy's results by purely chemical means. They also produced some elements in greater quantities than Davy.
In their continuing pursuit to out-do Davy, Gay-Lussac and Thenard announced the discovery of boron in 1808 just nine days before Davy did--the first clear victory for the French team. Gay-Lussac and Thenard reacted potassium metal with boric acid, isolating an olive-gray substance that they claimed to be the new element boron. Davy had produced a similar substance a year earlier, but failed to identify it.
The element boron appears in a wide variety of compounds that have different colors and consistencies. Although boron in minute amounts is an essential plant nutrient, slightly higher concentrations are toxic to plants, and the role boron plays in plant life remains mysterious. Large deposits of boron minerals are found in only a few places throughout the world, mainly near ancient volcanos.
Boron's value has been recognized and exploited for centuries. A complex compound of boron, called borax, is an important ingredient in soap, detergent, and laundry starch, as well as being used in the manufacture of leather and paper. In the early 1800s, the Dutch had a nearly complete monopoly on the borax market, but French chemist Anselme Payen invented a cheaper way to produce borax. Instead of refining it from ore, he prepared borax from boric acid, which he obtained from volcanic gases in Italy. Soon Payen was selling borax for just one-third of the price charged by the Dutch.
Scientific investigation of boron was largely neglected until 1892, when Henri Moissan (1852-1907) prepared boron of more than 98 percent purity for the first time. In 1912, German chemist Alfred Stock (1876-1946) began to explore the nature of boron hydrides, which would eventually prove invaluable as a high-energy rocket fuel additive. Stock discovered, purified, and characterized several of the compounds, but was able to obtain only small amounts. Scientists later found methods to produce greater yields, and today boron hydrides are used in the manufacture of natural and synthetic rubber.
Other boron compounds have multiple uses in industry and science. For example, for industrial grinding purposes, boron is even better than diamond in certain respects, and boron nitride crystals have already become an important synthetic abrasive. Other industrial processes that depend on boron include electroplating, glassmaking, ore refining, and pharmaceutical preparation. Boron compounds are also essential ingredients of modern detergents, water softeners, toothpastes, mouthwashes, cosmetics, and other familiar products.
Fibers of boron, held together with epoxy, have even been used in the construction of very lightweight, high-speed aircraft such as the F-14 and F-15 jet planes. The main drawback of these materials is cost. When they were first produced industrially, they were worth more than their weight in gold, and their price has not dropped as much as that of alternative materials.
This is the complete article, containing 702 words
(approx. 2 pages at 300 words per page).
