Sulfur elemental phosphorus

A rather different series of cyclic thiophos-phate(III) anions [(PS2) ]" is emerging from a study of the reaction of elemental phosphorus with polysulfidic sulfur. Anhydrous compounds... 

Steel is essentially iron with a small amount of carbon. Additional elements are present in small quantities. Contaminants such as sulfur and phosphorus are tolerated at varying levels, depending on the use to which the steel is to be put. Since they are present in the raw material from which the steel is made it is not economic to remove them. Alloying elements such as manganese, silicon, nickel, chromium, molybdenum and vanadium are present at specified levels to improve physical properties such as toughness or corrosion resistance. 

The following sections summarize only the most prominent interactions between the elemental cycles and the links in the hydrologic cycle. Water also plays a role in many chemical and biological reactions that are beyond the scope of this discussion. The carbon, nitrogen, sulfur, and phosphorus cycles are discussed in detail in Chapters 11, 12, 13, and 14, respectively. 

The element phosphorus, like nitrogen, is essential to plant and animal life. Although phosphorus was not identified and isolated until 1669, phosphorus-containing materials have been used as fertilizers since ancient times, usually from bird droppings, fish, and bone. The first phosphoric acid was made by treating bone ashes with sulfuric acid. This marked the beginning of the commercial fertilizer industry. Eventually, mined phosphate rock, a poor fertilizer by itself, was substituted for bones as a raw material for phosphoric acid in the mid-1880s. 

Elemental phosphorus is only one of several elements whose structures are polyatomic species. Another is the structure of elemental sulfur, which consists of puckered S8 rings ... 

The impurities in pig iron, the iron formed in a blast furnace, that make it brittle include four elements phosphorus and silicon, two elements that came from the silicate and phosphate minerals that contaminated the original ore, and carbon and sulfur that came from the coke. 

Clement, R. et al., J. Chem. Soc., Dalton Trans., 1979, 1566 When very finely divided metals (iron, manganese, nickel or zinc) are heated with elemental phosphorus and sulfur in evacuated ampoules to form the title compounds, explosions may occur, even at temperatures as low as 150-200°C. 

Before we get any further, I want to divide the chemical elements into two classes to facilitate an understanding of the structural chemistry of molecules. The first class includes those elements that form more than one chemical bond at a time. Carbon typically makes four chemical bonds and provides an example of such an element. Oxygen, nitrogen, sulfur, and phosphorus provide four additional examples of elements that typically make more than one chemical bond. Elements in this class provide for structural complexity, since, in principle at least, they can make straight chains, branched chains, cyclic structures, and so on. 

The major elements phosphorus and sulfur and the trace elements sodium, potassium, magnesium, calcium, chlorine, iodine, manganese, iron, cobalt, nickel, copper, and zinc, and a few others, play specific, critical roles in life. Several others occur in living systems but may not be essential for life. 

Elemental sulfur is not nearly so exotic as elemental phosphorus. In air, snlfnr jnst sits there while white phosphorus bursts into flame. Snlfnr seems sort of dnll, like an aging uncle. 

Lanthanum is a soft silvery-white metal that, when cut with a knife, forms an oxide with the air (tarnishes) on the exposed area. It is the most reactive of the elements in the series. It reacts slightly with cold water but rapidly with hot water, producing hydrogen gas (H ) and lanthanum oxide (La O ). It directly interacts with several other elements, including nitrogen, boron, the halogens, carbon, sulfur, and phosphorus. 

The phosphate concentration in the tailings is upgraded to a level adequate for commercial exploitation through removal of the nonphosphate sand particles by flotation [32], in which the silica solids are selectively coated with an amine and floated off following a slurry dewatering and sulfuric acid treatment step. The commercial quality, kiln-dried phosphate rock product is sold directly as fertilizer, processed to normal superphosphate or triple superphosphate, or burned in electric furnaces to produce elemental phosphorus or phosphoric acid, as described in Section 9.2. 

By far the most important derivative of sulfuric acid is phosphoric acid. It has been unknowingly used as fertilizer for hundreds of years. The wet process method of manufacture was important until 1920, when furnace acid began increasing in popularity. The wet process, however, has made a comeback because of plant design improvements 60% of phosphoric acid was made by this method in 1954, 88% in 1974, and over 90% currently. The furnace process is used only to make concentrated acid (75-85%) and pure product. It is very expensive because of the 2000 °C temperature required. In the furnace process phosphate rock is heated with sand and coke to give elemental phosphorus, which is then oxidized and hydrated to phosphoric acid. A simplified chemical reaction is ... 

Lanthanum combines with nitrogen, carbon, sulfur and phosphorus at elevated temperatures, forming binary salts. Also, with metalloid elements such as boron, silicon, selenium, and arsenic, similar reactions occur at high temperatures forming similar binary compounds. 

The metal reacts with halogens above 200°C forming its trihalides. It combines with nitrogen above 1,000°C producing a nitride, YN. It combines at elevated temperatures forming binary compounds with most nonmetals and some metalloid elements such as hydrogen, sulfur, carbon, phosphorus, silicon, and selenium. 

When atoms combine with each other there is formed a chemical entity termed a molecule. If two or more atoms of the same element combine there is formed a molecule of an element for example oxygen (02), hydrogen (H2), nitrogen (N2), sulfur (Sg), phosphorus (P4), etc, the subscript denoting the number of atoms in the elemental molecule. If two or more different atoms combine, there is formed a molecule of a chemical compound, such. as water (H2O), sodium chloride (NaCl), sulfuric acid (H2S04), etc... 

The Union of Two Elementary Substances.— The most obvious way in which to prepare a binary compound is by the union of the two constituent elements, though in many cases this is not the most practicable way. Sometimes, the elements are first prepared in pure form and are then combined in other cases, the preparation of the elements and their union is effected in one operation, as in the manufacture of calcium carbide and carborundum. In general, the more dissimilar the two elements the more likely they are to combine readily, but elements of the same general kind sometimes combine with ease, as is the case with chlorine and iodine, sulfur and phosphorus, or sodium and lead. 

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