Lithium chemical properties

Chemical Properties. Trimethylpentanediol, with a primary and a secondary hydroxyl group, enters into reactions characteristic of other glycols. It reacts readily with various carboxyUc acids and diacids to form esters, diesters, and polyesters (40). Some organometaUic catalysts have proven satisfactory for these reactions, the most versatile being dibutyltin oxide. Several weak bases such as triethanolamine, potassium acetate, lithium acetate, and borax are effective as stabilizers for the glycol during synthesis (41). 

Lithium cyanide [2408-36-8] mbidium cyanide [19073-56 ] and cesium cyanide [21159-32-0] are white or colorless salts, isomorphous with potassium cyanide. In physical and chemical properties these cyanides closely resemble sodium and potassium cyanide. As of this writing these cyanides have no industrial uses. 

The alkali metals form a homogeneous group of extremely reactive elements which illustrate well the similarities and trends to be expected from the periodic classification, as discussed in Chapter 2. Their physical and chemical properties are readily interpreted in terms of their simple electronic configuration, ns, and for this reason they have been extensively studied by the full range of experimental and theoretical techniques. Compounds of sodium and potassium have been known from ancient times and both elements are essential for animal life. They are also major items of trade, commerce and chemical industry. Lithium was first recognized as a separate element at the beginning of the nineteenth eentury but did not assume major industrial importance until about 40 y ago. Rubidium and caesium are of considerable academic interest but so far have few industrial applications. Francium, the elusive element 87, has only fleeting existence in nature due to its very short radioactive half-life, and this delayed its discovery until 1939. 

The Group 1 elements are soft, low-melting metals which crystallize with bee lattices. All are silvery-white except caesium which is golden yellow "- in fact, caesium is one of only three metallic elements which are intensely coloured, the other two being copper and gold (see also pp. 112, 1177, 1232). Lithium is harder than sodium but softer than lead. Atomic properties are summarized in Table 4.1 and general physical properties are in Table 4.2. Further physical properties of the alkali metals, together with a review of the chemical properties and industrial applications of the metals in the molten state are in ref. 11. 

The mean value for this triad is reasonably close to Berzelius value for bromine of 78.383. Dobereiner also obtained a triad involving some alkali metals, sodium, lithium, and potassium, which were known to share many chemical properties ... 

One early attempt to organize the elements clustered them into groups of three, called triads, whose members display similar chemical properties. Lithium, sodium, and potassium, for example, have many common properties and were considered to be a triad. This model was severely limited, for many elements could not be grouped into triads. The triad model is just one of nearly 150 different periodic arrangements of the elements that have been proposed. 

Lithium compounds, not lithium metal, are used in the treatment of some types of mental disorders. The chemical properties of lithium metal are very different from lithium compounds containing the ion, Li+. Li metal is very reactive with water, forming the strong base, LiOH, and hydrogen gas and releasing much heat, none of which are good for the human body. 

In order to avoid the use of lead compounds on environmental grounds, lithium fluoride (liF) has been chosen to obtain super-rate burning of nitramine composite propellants.P7281 Typical chemical compositions of HMX composite propellants-with and without liF are shown in Table 7.4. The non-catalyzed HMX propellant is used as a reference pyrolant to evaluate the effect of super-rate burning. The HMX particles are of finely divided, crystalline (3-HMX with a bimodal size distribution. Hydroxy-terminated polyether (HTPE) is used as a binder, the OH groups of which are cured with isophorone diisocyanate. The chemical properties of the HTPE binder are summarized in Table 7.5. 

Lithium metal is highly reactive but less so than other alkah metals. Its chemical properties, however, are more like those of the alkaline earth metals. 

The unique feature about anionic polymerization of diene to produce homopolymer was that the microstructure of the homopolymer could be altered and changed at will to produce unique physical and chemical properties. These microstructural changes can be introduced before, after or during the polymerization. For example, chelating diamines, such as tetramethyl ethylene and diamine (TMEDA) (18), with the alkyl-lithium catalyst have been used to produce polymer with 80 1,2 addition products, while the use of dipiperidine ethane (DPE),with same catalyst has produced polybutadiene with 100 1,2 addition product. 

Chemical properties.—Sodium chloride is necessary for the proper performance of the physiological functions of the body the other alkali chlorides are said to be poisonous 64 with small animals. According to C. Richet, the maximum dose per kilogram of animal, with subentaneous injections, is 01 grm. with lithium chloride 0 5 grm. with potassium chloride l O grm. with rubidium chloride and 0 5 grm. with caesium chloride. Lithium chloride is very hygroscopic sodium chloride is less hygroscopic, but it takes up O 5 to 0> 6 per cent, moisture on exposure... 

The same argument can be made for each alkali atom because there is only one outer electron, one can model an alkah atom as a hydrogen-like atom with one electron and a nucleus made up of the true nucleus and the inner electrons. As above, this argument hinges on the fact that the inner electrons tend to be in the lowest possible states, while the Pauli exclusion principle forbids any two electrons from occupying the same state. And indeed, spectral data for alkali atoms resembles spectral data for hydrogen. Moreover, the chemical properties of the alkali atom is similar. For example, each combines easily with chlorine to form a salt such as potassium chloride, lithium chloride... 

The physical and chemical properties of the tetrahydroborates show more contrasts than the salts of nearly any other anion. The alkali metal salts are the most stable. In dry air, NaBH4 is stable at 300°C and in vacuo to 400°C with only partial decomposition. In contrast, several tetrahydroborates, including the titanium, thallium, gallium, copper, and silver salts, are unstable at or slightly above ambient temperatures. The chemical and physical properties of the tetrahydroborates are closely related to molecular structure. Sodium tetrahydroborate, which is typical of the alkali metal tetrahydroborates except for the lithium salt, has a face-centered cubic (fee) crystal lattice which is essentially ionic and contains the tetrahedral [BHJ- anion. The tetrahydroborates of the polyvalent metals are in many cases the most volatile derivatives of these metals known. Aluminum tris(tetrahydroborate)... 

The chemical properties of lithium hydride, methane, and hydrogen fluoride are in accord with the above formulations. Thus, when the bond to the hydrogen is broken, we might expect it to break in the senseLi Hefor... 

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