Sodium compounds with oxygen

It is never found in its free, pure form in nature. Although less reactive than the metals with fewer electrons in their outer orbits, boron is usually compounded with oxygen and sodium, along with water, and in this compound, it is referred to as borax. It is also found as a hard, brittle, dark-brown substance with a metallic luster, as an amorphous powder, or as shiny-black crystals. 

Electrovalent bonds are formed between oppositely charged ions, and typically a metal donates electrons to a nonmetal. For example, sodium chloride (common salt, an important constituent of the body s fluids) is written as Na Cl. For sodium chloride only one electron is involved in the transfer and the molecular formula is written as NaCl. However, if sodium forms an ionic compound with oxygen, an oxygen atom needs two electrons to form an ion, so it will need to have two sodium atoms donating electrons ... 

The compound of sodium and oxygen known as sodium superoxide (Na02) has been prepared by two different methods. According to the first method a solution of sodium in liquid ammonia, when rapidly oxidized, yields a product corresponding to the empirical formula NaaOs, which is thought to be a mixture of sodium superoxide and sodium peroxide in the ratio of 4 to 1. By the second method, which has been more fully explored in this study, sodium superoxide is prepared by the treatment of sodium peroxide with oxygen under conditions of high temperature and pressure. 

These equations tell us that the reverse process proton transfer from acids to bicarbon ate to form carbon dioxide will be favorable when of the acid exceeds 4 3 X 10 (pK, < 6 4) Among compounds containing carbon hydrogen and oxygen only car boxylic acids are acidic enough to meet this requirement They dissolve m aqueous sodium bicarbonate with the evolution of carbon dioxide This behavior is the basis of a qualitative test for carboxylic acids... 

Salts are formed as with oxygen-containing compounds. For example, C2H5 — S—Na is named either sodium ethanethiolate or sodium ethyl sulfide. If mercapto- has been used as a prefix, the salt is named by use of the prefix sulfido- for —S . 

The principal product of the reaction of the alkali metals with oxygen varies systematically down the group (Fig. 14.15). Ionic compounds formed from cations and anions of similar radius are commonly found to he more stable than those formed from ions with markedly different radii. Such is the case here. Lithium forms mainly the oxide, Li20. Sodium, which has a larger cation, forms predominantly the very pale yellow sodium peroxide, Na202. Potassium, with an even bigger cation, forms mainly the superoxide, K02, which contains the superoxide ion, O,. ... 

Silicon w is first isolated and described as an element in 1824 by Jdns Jacob Berzelius, a Swedish chemist. Silicon does not occur uncombined in nature, i.e.- as an element. It is found in practically aU rocks as well as in sand, clays, and soils, combined either with oxygen as silica (Si02= silicon dioxide) or with oxygen plus other elements (e.g., aliuninum, mcignesium, calcium, sodium, potassium, or iron) as silicates. Its compounds also occur in all natural waters, in the atmosphere (as siliceous dust), in many plants, and in the skeletons, tissues, and body fluids of some animals. 

The system 35a + 35b is in equilibrium in solution the interconversion formally involves migration of the benzoyl group from an oxygen to a nitrogen atom. Benzoylation of the sodium salt of phenanthridone at — 20° gives rise to the 0-benzoyl derivative 35a, which is stable at low temperatures. When heated alone or in CH2C12 solution, 35a converts to the JV-benzoyl derivative 35b, the form that is obtained directly by benzoylation at room temperature. The compounds with X = p-MeO or p-Cl show similar melting behaviors (80). 

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