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Gaffer Variety:
Elements 6 SN2 008:
By Willie Gaffer:
Lithium (Li) is a soft, silvery, highly reactive metallic element
that is used as a heat transfer medium, in thermonuclear weapons, and in
various alloys, ceramics, and optical forms of glass. The atomic number is 3
and the atomic weight is 6.939; Lithium has a melting point of 179°C and a
boiling point 1of 317°C. The specific gravity is 0.534 and the valence is
1. We find it group 1A of our periodic table just under hydrogen. Although it
ranks 35th in order of abundance of the elements in the crust of the earth, it
does not occur in nature in the
lithium is found in useable quantities in such minerals as spodumene, lepidolite, amblygonite, and petalite. It makes up roughly 0.002 percent of the Earth's crust. It is normally extracted as lithium hydroxide, carbonate, or sulfate, which can be converted to other compounds. Lithium metal is made by electrolyzing a molten mixture of lithium chloride and potassium chloride. The metal, which can be drawn into wire and rolled into sheets, is softer than lead but harder than the other alkali metals. Lithium floats on water, reacting with it to yield lithium hydroxide (LiOH) and hydrogen gas. It is commonly kept coated with petrolatum because it reacts with the moisture in the air.
Natural lithium exists as two isotopes: lithium-7 and lithium-6. Other radioactive isotopes have been produced, but they all have half-lives of less than one second. Lithium was used (1932) as the target metal in the pioneering work of John Cockcroft and Ernest Walton in transmuting nuclei by artificially accelerated atomic particles; each lithium nucleus that absorbed a proton became two helium nuclei. The bombardment of lithium-6 with slow neutrons produces helium and tritium.
Lithium is chemically active, readily losing one of its three electrons to form compounds containing the Li+ cation. Many of these differ markedly in solubility from the corresponding compounds of the other alkali metals.
Several lithium compounds have practical applications. Lithium hydride (LiH) is a useful source of hydrogen. It release hydrogen when it is treated with water. It is also used to produce lithium aluminum hydride (LiAlH4), which can reduce aldehydes, ketones, and carboxylic esters to alcohols.
Lithium hydroxide (LiOH) is used in making lithium salts which are used as thickeners in lubricating greases. Lithium hydroxide is also used as an additive in the electrolyte of alkaline storage batteries. Lithium carbonate has been used in the treatment of bipolar disorder and some forms of depression. This is only a surface view. There are many other uses for this metal just as there is for sodium. In fact, lithium resembles sodium in its behavior.
Beryllium (Be) is a lightweight, corrosion-resistant, rigid, steel-gray metallic element used as an aerospace structural material. The melting point of 1,278°C makes it very useful in this application and in nuclear reactors. The atomic number 4. The atomic weight is 9.0122 and the boiling point is 2,970°C. Beryllium has a specific gravity 1.848 and a valence of 2. Beryllium is an alkaline earth metal putting it in group 2A of the periodic table.
Beryllium, ranks about 51st in natural abundance among the elements in the earth's crust. It has a high strength per unit weight. It tarnishes only slightly in air, becoming covered with a thin layer of oxide. The ability of beryllium to scratch glass is usually ascribed to this oxide coating. Beryllium compounds are generally white (or colorless in solution) and show great similarity in chemical properties to the corresponding compounds of aluminum. This similarity makes it difficult to separate beryllium from the aluminum that is almost always present in beryllium ores.
The addition of beryllium to some alloys often results in products that have high heat resistance, improved corrosion resistance, greater hardness, greater insulating properties, and better casting qualities. Many parts of supersonic aircraft are made of beryllium alloys because of their lightness, stiffness, and dimensional stability. Other applications make use of the nonmagnetic and non-sparking qualities of beryllium and the ability of the metal to conduct electricity.
X rays pass through pure beryllium, making it useful as window material for X-ray tubes. One very important use for Beryllium and its oxide, beryllia, is as a moderator, or blanket, around the core of a nuclear reactor. It has the effect of slowing down and sometimes capturing neutrons.
Beryllium and its oxide are being used more frequently in industry. Besides its importance in aircraft and X-ray tubes, beryllium is used in computers, lasers, televisions, oceanographic instruments, and personal body armor.
Boron is a soft, brown, amorphous or crystalline element. It’s place is in group 3A making it a nonmetallic element. The atomic number is 5 and the atomic weight is 10.811 It has a very high melting point at 2,300°C and a sublimation point at 2,550°C. In this context, sublimation means to change from a solid to a gas without going through the liquid stage. The specific gravity of Boron is 2.34 and the valence is 3. Boron ranks about 38th in natural abundance among the elements in the earth's crust.
Men have known about Borax, a compounds of boron (calcium
borate), since ancient times. Think
Boron does not react with water, hydrochloric acid, or air at ordinary temperatures. When red hot it combines directly with nitrogen to form boron nitride (BN), and with oxygen to form boron oxide (B2O3). With metals it forms borides, such as magnesium boride (Mg3 B2). The original sources of boron compounds were the minerals borax and boric acid.
Although with a valence of 3 boron ought to behave like aluminum, but it is much more like carbon and silicon in chemical properties. In its compounds, boron acts like a nonmetal, but unlike most nonmetals, pure boron is an electrical conductor, like the metals and like carbon (graphite). Crystalline boron is similar to diamond in appearance and optical properties, and is almost as hard as diamond. Most extraordinary in their anomalous similarity to the compounds of silicon and carbon are the boron hydrides. The boron compounds of industrial importance include borax (Na2 B4O7· 10H20), boric acid (H3BO3), and boron carbide (B4C). Borax is used in cleaning compounds, glass and ceramics, fertilizers, paper and paints, and fire retardants. Boric acid is used medically for its astringent and antiseptic properties. Boron carbide is used as an abrasive and alloying agent.