State element

The lanthanides, distributed widely in low concentrations throughout the earth s cmst (2), are found as mixtures in many massive rock formations, eg, basalts, granites, gneisses, shales, and siUcate rocks, where they are present in quantities of 10—300 ppm. Lanthanides also occur in some 160 discrete minerals, most of them rare, but in which the rare-earth (RE) content, expressed as oxide, can be as high as 60% rare-earth oxide (REO). Lanthanides do not occur in nature in the elemental state and do not occur in minerals as individual elements, but as mixtures. 

Elemental sulfur in either its ore or its refined state can generaUy be recognized by its characteristic yeUow color or by the generation of sulfur dioxide when it is burned in air. Its presence in an elemental state or in a compound can be detected by heating the material with sodium carbonate and mbbing the fused product on a wet piece of silver metal. A black discoloration of the silver indicates the presence of sulfur. The test is quite sensitive. Several other methods for detecting smaU amounts of elemental sulfur have also been developed (34). 

Chlorine. Chlorine, the material used to make PVC, is the 20th most common element on earth, found virtually everywhere, in rocks, oceans, plants, animals, and human bodies. It is also essential to human life. Eree chlorine is produced geothermally within the earth, and occasionally finds its way to the earth s surface in its elemental state. More usually, however, it reacts with water vapor to form hydrochloric acid. Hydrochloric acid reacts quickly with other elements and compounds, forming stable compounds (usually chloride) such as sodium chloride (common salt), magnesium chloride, and potassium chloride, all found in large quantities in seawater. 

J. C. Carver, G. K. Schweitzer, and T. A. Carlson. J. Chem. Phys. 57, 973, 1972. This paper deals with multiplet splitting effects, and their use in distinguishing different element states, in transition metal complexes. 

Because of their reactivity, the halogens do not occur in the free elemental state but they are both widespread and abundant in the form of their ions, X. Iodine also occurs as iodate (see below). In addition to large halide mineral deposits, particularly of NaCl and KCl, there are vast quantities of chloride and bromide in ocean waters and brines. 

Formal charge (Section 2.3) The difference in the number of electrons owned by an atom in a molecule and by the same atom in its elemental state. 

Table 6-VI lists some properties of the halogens. In the elemental state, the halogens form stable diatomic molecules. This stability is indicated by the fact that it takes extremely high temperatures to disrupt halogen molecules to form the monatomic species. For example, it is known that the chlorine near the surface of the sun, at a temperature near 6000°C, is present as a gas consisting of single chlorine atoms. At more normal temperatures, chlorine atoms react with each other to form molecules ...

The chemical reactions appear simple. They begin with pure sulfur (which occurs in natural deposits in the elemental state). First, sulfur is burned to give gaseous sulfur dioxide, S02. Next, the S02 is further oxidized, catalytically, to sulfur trioxide, SO ,. Finally, addition of water forms sulfuric acid. The reactions are ... 

Silicon is the second most abundant element in the earth s crust. It occurs in sand as the dioxide Si02 and as complex silicate derivatives arising from combinations of the acidic oxide Si02 with various basic oxides such as CaO, MgO, and K20. The clays, micas, and granite, which make up most soils and rocks, are silicates. All have low solubility in water and they are difficult to dissolve, even in strong acids. Silicon is not found in the elemental state in nature. 

Argon is found only in the elemental state. Air contains about 1 % argon. 

Silicon in the elemental state has important electronic applications as a semiconductor that were developed only during the last decade. The discovery of these uses was possible only after methods were developed for preparing silicon of extremely high purity. Reduction of Si02 with... 

A) Cold vapour technique. This procedure is strictly confined to the determination of mercury,45 which in the elemental state has an appreciable vapour pressure at room temperature so that gaseous atoms exist without the need for any special treatment. As a method for determining mercury compounds the procedure consists in the reduction of a mercury(II) compound with either... 

Arsenic and antimony are metalloids. They have been known in the pure state since ancient times because they are easily obtained from their ores (Fig. 15.3). In the elemental state, they are used primarily in the semiconductor industry and in the lead alloys used as electrodes in storage batteries. Gallium arsenide is used in lasers, including the lasers used in CD players. Metallic bismuth, with its large, weakly bonded atoms, has a low melting point and is used in alloys that serve as fire detectors in sprinkler systems the alloy melts when a fire breaks out nearby, and the sprinkler system is activated. Like ice, solid bismuth is less dense than the liquid. As a result, molten bismuth does not shrink when it solidifies in molds, and so it is used to make low-temperature castings. 

Oxygen and sulfur occur naturally in the elemental state sulfur forms chains... 

Volatilization is also a dominant transport mode for mercury, which is the most volatile metal in its elemental state. As with lead, a key reaction that can increase the volatility of mercury is formation of an organometallic compound. In this case, the reactions take place in water and are primarily biological, being mediated by bacteria commonly found in the upper levels of sediments. These reactions and their importance in the global mercury cycle are discussed in some detail later in the chapter. 

Data on the electrochemistry of the telluride ion in alkaline media are relatively limited. Mishra et al. [53] studied the oxidation of Te to Te° at solid electrodes, focusing on the intermediate step(s) of this process, and in particular, the possibility of detecting ditelluride Te via rotating ring disk electrode (RRDE) methodology. Oxidation beyond the elemental state to TeO and TeO was also studied using cyclic and hydrodynamic voltammetry. 

In principle, any element whose Ellingham line lies below the Ellingham line of a specified element, is capable of reducing the oxide of the specified element to the elemental state. In practice, however, only the nonmetals, carbon, hydrogen and silicon, and the met-... 

Here it is assumed that upon fracture of a grain boundary, half of the segregant is left on each free surface, and that the segregant atoms pack at the same density as they would in the pure elemental state. 

Mercury and the noble metals are found in nature in their elemental forms however, they are generally unreactive and so their occurrence in the soil solution is limited. Some elements, such as sulfur, can be reduced to their elemental state (see Figure 4.8) by soil microorganisms however, they can also easily be both oxidized and the oxidized forms reduced and so are rarely found in their elemental form in soil. 

Although laser ablation is clearly becoming more popular (as shown in Fig. 9.1), it is difficult to produce fully quantitative data because of problems in matrix matching between sample and standard (see below and Section 13.3). There are also likely to be variations in ablation efficiency in multi-component mixtures, leading to over- or under-representation of particular phases of the sample. It is also unlikely that all ablation products will enter the plasma in the elemental state, or that different particle sizes produced by ablation will have the same compositions. Ablation products may, therefore, not be truly representative of the sample (Morrison et al. 1995, Figg et al. 1998). Additionally, limits of detection for most elements are approximately... 

A Metals in their elemental state have no charge. Designations such as Al3+ refer to the metal in, or from, a compound. If you have a piece of metal, you should use Al, or possibly Al°. 

Boron remarks on its crystal structure. The atomic and physical properties of boron are reported in 5.13.2 with a few data about its crystal structures in the elemental state. A few more comments will be added here in order to insert also boron in this short summary of the crystal properties of the various elements. In this general although partial picture, the peculiar characteristics of boron have indeed to be underlined. 

Imagine that scientists have successfully synthesized element X, with atomic number 126. Predict the values of n and 1 for the outermost electron in an atom of this element. State the number of orbitals there would be in this energy sublevel. 

In its elemental state, strontium is a relatively soft, pale yellow metal somewhat similar to elemental calcium. When freshly cut, strontium has a silvery shine to its surface that soon turns grayish as it is oxidixed by atmospheric oxygen (2Sr + 2SrO) and nitrogen (3Sr +... 

Strontium metal is not found in its elemental state in nature. Its salts and oxide compounds constitute only 0.025% of the Earths crust. Strontium is found in Mexico and Spain in the mineral ores of strontianite (SrCO ) and celestite (SrSO ). As these ores are treated with hydrochloric acid (HCl), they produce strontium chloride (SrCy that is then used, along with potassium chloride (KCl), to form a eutectic mixture to reduce the melting point of the SrCl, as a molten electrolyte in a graphite dish-shaped electrolysis apparatus. This process produces Sr cations collected at the cathode, where they acquire electrons to form strontium metal. At the same time, Cl anions give up electrons at the anode and are released as chlorine gas Cl T. 

Germanium is not found in its free elemental state because it is much too reactive. For the most part, it is found combined with oxygen, either as germanium monoxide or as germanium dioxide. Also, it is recovered from the ores of zinc, copper, and arsenic and the flue deposits of burning coal. 

Germanium, the 52nd most abundant element in the Earths crust, is widely distributed, but never found in its natural elemental state. It is always combined with other elements, particularly oxygen. 

Bismuth is the 70th most abundant element, and it is widely spread over the Earths crust, but in very small amounts. There are no major concentrated sources. It occurs both in the free elemental state and in several ores. The major ore, bismuthinite (B S ), is found in South America. 

Uses/Sources. Manufacture of rat poisons for smoke screens gas analysis fireworks in ammunitions such as mortar, artillery shells, and grenades the elemental material is produced as a by-product in the production of phosphate fertilizer it does not occur in the elemental state in nature... 

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