Carbonates, Nitrates, Sulfates, and Phosphates

Some of the Group IA and IIA metals are found in nature in the form of carbonates, silicates, nitrates, and phosphates. For example, calcium carbonate is one of the most important naturally occurring compounds, and it is found in several forms. The most common form of calcium carbonate is limestone, which is used extensively as a building stone as well as the source of lime. Other forms include chalk, calcite, aragonite, Iceland spar, marble, and onyx. Many other materials such as egg shells, coral, pearls, and seashells are composed predominantly of calcium carbonate. Thus, it is one of the most widely occurring compounds in nature. 

Because of its use in the manufacture of fertilizers, calcium phosphate is a compound of enormous importance. After being mined, it is converted into Ca(H2P04)2 by treating it with sulfuric acid. This converts the insoluble Ca3(P04)2 into a soluble, more efficient form (see Section 13.9). The reaction can be written as 

Sodium and potassium nitrates have been of enormous significance in the past because the preparation of nitric acid for many years was by means of the reaction 

The major deposits of alkali nitrates found in Chile were vital for making nitric acid, which is necessary to prepare almost all types of explosives and propellants. Of course, nitric acid is now obtained by the catalytic oxidation of ammonia by the Ostwald process (see Chapter 12). 

For many centuries, sodium carbonate has been recovered from the beds of dried lakes and inland seas. It is also found in the mineral trona, Na2C03 NaHC03 2H20, which is now the commercial source of the compound in the United States. Sodium carbonate ranks high on the list of chemicals most used, and the majority of it is used in the manufacture of glass. 

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Some of the important compounds containing the group IA and IIA metals are the carbonates, nitrates, sulfates, and phosphates. We have already mentioned the mineral trona as the source of sodium carbonate. Calcium carbonate is found in many forms that include chalk, calcite, aragonite, and marble, as well as in egg shells, coral, and seashells. In addition to its use as a building material, calcium phosphate is converted into fertilizers in enormous quantities (see Chapter 14). 

Oxygen occurs in all kinds of minerals. Some common examples include the oxides, carbonates, nitrates, sulfates, and phosphates. Oxides are chemical compounds that contain oxygen and one other element. Calcium oxide, or lime or quicklime (CaO), is an example. Carbonates are compounds that contain oxygen, carbon, and at least one other element. Sodium carbonate, or soda, soda ash, or sal soda (Na2C03), is an example. It is often found in detergents and cleaning products. 

Without life there would be no carbon cycle on earth. But this is also true for all other elements as well as carbonate, nitrate, sulfate and phosphate all also cannot be reduced by simple chemical processes in the climate system. Deep in the earth, however, we cannot exclude - even hypothesizing the existence of elemental carbon - reducing chemical regimes, turning elements on geological timescales. 

It is important to learn the names and valences of the five most common polyatomic ions nitrate, carbonate, chlorate, sulfate, and phosphate. These ions form many of the chemicals in nature and in common use. While the task seems overwhelming, it may help to learn the "big five" using a mnemonic, or memory aid. You can use the following mnemonic to remember their names, valences, and number of oxygen atoms ... 

The physical and chemical properties of elemental thorium and a few representative water soluble and insoluble thorium compounds are presented in Table 3-2. Water soluble thorium compounds include the chloride, fluoride, nitrate, and sulfate salts (Weast 1983). These compounds dissolve fairly readily in water. Soluble thorium compounds, as a class, have greater bioavailability than the insoluble thorium compounds. Water insoluble thorium compounds include the dioxide, carbonate, hydroxide, oxalate, and phosphate salts. Thorium carbonate is soluble in concentrated sodium carbonate (Weast 1983). Thorium metal and several of its compounds are commercially available. No general specifications for commercially prepared thorium metal or compounds have been established. Manufacturers prepare thorium products according to contractual specifications (Hedrick 1985). 

In aqueous media lutetium occurs as tripositive Lu3+ ion. All its compounds are in +3 valence state. Aqueous solutions of all its salts are colorless, while in dry form they are white crystalline solids. The soluble salts such as chloride, bromide, iodide, nitrate, sulfate and acetate form hydrates upon crystallization. The oxide, hydroxide, fluoride, carbonate, phosphate, and oxalate of the metal are insoluble in water. The metal dissolves in acids forming the corresponding salts upon evaporation of the solution and crystallization. 

When a second ITP was cascaded with the first ITP, known as concentration-cascade ITP, SC2 was filled with LE (as in SCI). This concentration-cascade ITP was achieved for 14 anions (200 pM) within 600 s (see Figure 6.18). When ITP was followed by CZE (ITP-CZE), SC2 was filled with a background electrolyte (not necessarily with the greatest mobility). ITP-CZE has been achieved for nitrate, fluoride, and phosphate (10 pM) in the presence of high contents of sulfate (800 pM) and chloride (600 pM) [631]. Subsequent work on the reproducibility on this on-chip ITP separation has been reported [632]. When ITP is performed at pH of greater than 7, there is a common problem of carbonate contamination caused by dissolved atmospheric C02 [633]. 

Defluorinated Phosphate Rock. There is substantial production of defluorinated phosphate rock for fertilizer use in Japan (about 100,000 mt/year). Ground, high-grade rock is mixed with small proportions of sodium carbonate or sulfate and wet-process acid. The mixture is calcined at a temperature of 1350°C in an oil-fired rotary kiln 45.0 m in length and 2.7 m in diameter. The product contains 38-42 percent P205 of which more than 90 percent is soluble in neutral ammonium nitrate solution and is an effective fertilizer on acid soils. During the production of defluorinated phosphate rock, substantially all fluorine is driven off. Sodium bifluoride (NaHF2) is recovered as a byproduct. A similar product is made in the United States, but it is mainly used for animal feed supplement. 

The dominant oxidation states for thallium are the mono and trivalent states. The thallous ion (TU) is colorless has a radius of 1.4 A, and usually exists as a six- or eight-coordinate structure in crystalline salts [1,2]. The thallous ion can produce a base that is weaker than KOH (i.e., TlOH). Thallium can also be considered a soft Lewis acid its softness is attributed to its d ° electron configuration. A variety of water-soluble thallous salts exist including the cyanide, nitrate, carbonate, sulfate, and phosphate. Insoluble salts such as the chloride (TlCl) or the sulfide (TljS) also exist. 

The water-soluble salts of the triphenylselenonium cation (C H6)sSe+, form, with perchloric acid and its salts, an extremely insoluble perchlorate. Bromates, chlorates, iodates, chlorides, bromides, phosphates, nitrates, sulfates and carbonates have no effect. This behavior allows a selective test for perchloric acid. 

All oxides and hydroxides of Mn except Mu207 are insoluble, as are Mn borate, carbonate, oxalate, phosphate, sulfide and sulfite, but the nitrate, sulfate and chloride are deliquescent. Seawater and some freshwater contain traces of MnCr, MnCl2, MtiHCOs"" and MnS04. 

Copper metals are widely used in equipment for handling various kinds of salt solutions including the nitrates, sulfates, and chlorides of sodium and potassium. Although alkaline sodium salts such as sih-cate, phosphate, and carbonate attack copper alloys at low rates, alkaline cyanide is aggressive and attacks copper alloys fairly rapidly because of the formation of soluble complex copper species such as Cu(CN), CuCCNlai- and CuCCNlg -. 

Thousands of compounds of the actinide elements have been prepared, and the properties of some of the important binary compounds are summarized in Table 8 (13,17,18,22). The binary compounds with carbon, boron, nitrogen, siUcon, and sulfur are not included these are of interest, however, because of their stabiUty at high temperatures. A large number of ternary compounds, including numerous oxyhaUdes, and more compHcated compounds have been synthesized and characterized. These include many intermediate (nonstoichiometric) oxides, and besides the nitrates, sulfates, peroxides, and carbonates, compounds such as phosphates, arsenates, cyanides, cyanates, thiocyanates, selenocyanates, sulfites, selenates, selenites, teUurates, tellurites, selenides, and teUurides. 

The chlorides, bromides, nitrates, bromates, and perchlorate salts ate soluble in water and, when the aqueous solutions evaporate, precipitate as hydrated crystalline salts. The acetates, iodates, and iodides ate somewhat less soluble. The sulfates ate sparingly soluble and ate unique in that they have a negative solubitity trend with increasing temperature. The oxides, sulfides, fluorides, carbonates, oxalates, and phosphates ate insoluble in water. The oxalate, which is important in the recovery of lanthanides from solutions, can be calcined directly to the oxide. This procedure is used both in analytical and industrial apptications. 

The carbonates, sulfates, nitrates, and haUdes of lead (except the yeUow iodide) are colodess. Bivalent lead forms a soluble nitrate, chlorate, and acetate a slightly soluble chloride and an insoluble sulfate, carbonate, chromate, phosphate, molybdate, and sulfide. Highly crystalline basic lead salts of both anhydrous and hydrated types are readily formed. Tetrabasic lead sulfate [52732-72-6] 4PbO PbSO, and the hydrated tribasic salt [12397-06-7] ... 

Oxo Ion Salts. Salts of 0x0 anions, such as nitrate, sulfate, perchlorate, iodate, hydroxide, carbonate, phosphate, oxalate, etc, are important for the separation and reprocessing of uranium, hydroxide, carbonate, and phosphate ions are important for the chemical behavior of uranium ia the environment (150—153). 

Ce(III) forms a water-insoluble hydroxide, carbonate, oxalate, phosphate, and fluoride sparingly soluble sulfate and acetate and soluble nitrate and chloride (and bromide). In solution the salts are only slightly hydrolyzed. The carbonate is readily prepared and is a convenient precursor for the preparation of other derivatives. The sparingly soluble sulfate and acetate decrease in solubihty with an increase in temperature. Calcination of most Ce(III) salts results in Ce02. 

The carbonates, sulfates, nitrates, and phosphates of the group IA and IIA metals are important materials in inorganic chemistry. Some of the most important compounds of the group IA and IIA elements are organometallic compounds, particularly for lithium, sodium, and magnesium, and Chapter 12 will be devoted to this area of chemistry. 

Plumes from biomass burning can also have unique signatures. For example, organics, ammonium, potassium, sodium, nitrate, nitrite, sulfate, chloride, phosphate, elemental carbon, and the anions of organic acids (formate, acetate, oxalate, etc.) have all been measured in particles in the plumes from burning vegetation (e.g., see Cofer et al., 1988 Andreae et al., 1988 and Artaxo et al., 1994). 

Salts of Ordinary Oxygen Acids.—Among the ordinary oxygen salts are included the oxyhalogens the nitrates and the nitrites the carbonates the phosphates, phosphites, and hypophosphites the sulfates and sulfites the borates and the silicates. These may be divided into (a) oxidizing salts and (b) reducing salts. 

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