Iodine abundance

Coleman ML, Eggenkamp HGM, Aranyossy JF (2001) Chlorine stable isotope characterization of solute transport in mudrocks, ANDRA. Actes des Jounces Scientifiques EDP Sciences, France, p 155-175 Curie I (1921) Sur le poids atomique du chloe dans quelques mineraux. CR Acad Sci (Paris) 172 1025-1028 Deruelle B, Dreibus G, Jambon A (1992) Iodine abundances in oceanic basalts implications for Earth dynamics. Earth Planet Sci Lett 108 217-227... 

Deruelle, B., Dreibus, G., Jambon, A. (1992) Iodine abundances in oceanic basalts Implications for Earth dynamics. Earth Planet. Sci. Lett., 108, 217-27. 

Iodine is sparingly soluble in water, which takes up not more than of its weight (1 lb. of water dissolves 1 grain of iodine). The solution has a pretty strong brownish-yellow colour, and the smell of iodine. Alcohol and ether dissolve iodine abundantly, forming deep-brown solutions. Free iodine, whether in the form of vapour or of solution, gives to starch a deep blue colour, which afibrds a very delicate test for iodine, as well as for starch. 

Many artificial (likely radioactive) isotopes can be created through nuclear reactions. Radioactive isotopes of iodine are used in medicine, while isotopes of plutonium are used in making atomic bombs. In many analytical applications, the ratio of occurrence of the isotopes is important. For example, it may be important to know the exact ratio of the abundances (relative amounts) of the isotopes 1, 2, and 3 in hydrogen. Such knowledge can be obtained through a mass spectrometric measurement of the isotope abundance ratio. 

Occurrence in Nature. About 99.6% of the earth s mass results from 32 of the chemical elements. The remaining 0.4% is apportioned among 64 elements, all of which are present as traces. Iodine is one of these 64. Estimates about abundance of the constituent elements of the Hthosphere place iodine 46th on a restricted Hst of 59 elements (37 very rare elements are excluded) and 61st on a Hst in which 96 elements are included. Iodine is, indeed, one of the scarcest of the nonmetaUic elements in the total composition of the earth (3). 

Although not abundant in quantity, iodine is distributed in rocks, soils, waters, plants, animal tissues, and foodstuffs (3,4). Excepting the possible occurrence of elemental iodine vapor in the air near certain iodine-rich springs, iodine never occurs free in nature. It is always found combined with other elements. 

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. 

Apart from the unstable (half-life 2.623 y) of which traces occur in uranium ores, the lanthanides are actually not rare. Cerium (66 ppm in the earth s crust) is the twenty-sixth most abundant of all elements, being half as abundant as Cl and 5 times as abundant as Pb. Even Tm (0.5 ppm), the rarest after Pm, is rather more abundant in the earth s crust than is iodine. 

Starches can be separated into two major components, amylose and amylopectin, which exist in different proportions in various plants. Amylose, which is a straight-chain compound and is abundant in potato starch, gives a blue colour with iodine and the chain assumes a spiral form. Amylopectin, which has a branched-chain structure, forms a red-purple product, probably by adsorption. 

The Zag meteorite fell in the western Sahara of Morocco in August 1998. This meteorite was unusual in that it contained small crystals of halite (table salt), which experts believe formed by the evaporation of brine (salt water). It is one of the few indications that liquid water, which is essential for the development of life, may have existed in the early solar system. The halite crystals in the meteorite had a remarkably high abundance of 128Xe, a decay product of a short-lived iodine isotope that has long been absent from the solar system. Scientists believe that the iodine existed when the halite crystals formed. The xenon formed when this iodine decayed. For this reason, the Zag meteorite is believed to be one of the oldest artifacts in the solar system. In this lab, you will use potassium-argon radiochemical dating to estimate the age of the Zag meteorite and the solar system. 

The silver gray metal can be cut with a knife, although it only melts at 1545 °C (for comparison, iron 1538 °C). It is the rarest of the "rare earths", but is nevertheless more abundant than iodine, mercury, and silver. Thulium has few applications, especially because it is relatively expensive. The element occurs naturally as a single isotope, namely 169Tm (compare bismuth). The artificial, radioactive 170Tm is a transportable source of X-rays for testing materials. Occasionally used in laser optics and microwave technology. 

TES-32 is the most abundant single protein product secreted by the parasite. It is also heavily labelled by surface iodination of live larvae (Maizels et al., 1984, 1987), and is known by monoclonal antibody reactivity to be expressed in the cuticular matrix of the larval parasite (Page et al, 1992a). TES-32 was cloned by matching peptide sequence derived from gel-purified protein to an expressed sequence tag (EST) dataset of randomly selected clones from a larval cDNA library (Loukas et al., 1999). Because of the high level of expression of TES-32 mRNA, clones encoding this protein were repeatedly sequenced and deposited in the dataset (Tetteh et al., 1999). Full sequence determination showed a major domain with similarity to mammalian C-type (calcium-dependent) lectins (C-TLs), together with shorter N-terminal tracts rich in cysteine and threonine residues. Native TES-32 was then shown to bind to immobilized monosaccharides in a calcium-dependent manner (Loukas et al., 1999). 

There are many natural sources of chlorine compounds, which is not surprising considering that it is the 20th most abundant element. Salt and salt water are widely available the Great Salt Lake contains 23% salt, and the Dead Sea contains about 30%. Because salt is so abundant, most minerals that contain chlorine are not important sources for economic reasons. Bromine is found in some salt brines and in the sea, as are some iodine compounds. 

Evidence of a different sort also indicates wide variability with respect to thyroid function. In endemic areas not all of the individuals exhibit endemic goiters, only certain individuals. These, it would be assumed, are individuals who for some reason connected with the production of thyroid hormone need more iodine than their fellows. Similarly, it may be noted that in areas where sea food is abundantly used and iodine is therefore relatively plentiful, there are still some individuals who develop simple goiter. 

Swindle TD, Podosek FA (1988) Iodine-Xenon dating. In Meteorites and the Early Solar System. Kerridge JF and Matthews MS (eds) University of Arizona Press, Tucson, p 1114-1146 Tang M, Lewis RS, Anders E (1988) Isotopic anomalies of Ne, Xe, and C in meteorites. I. Separation of carriers by density and chemical resistance. Geochim Cosmochim Acta 52 1221-1234 Tera F, Eugster O, Burnett DS, Wasserburg GJ (1970) Comparative study of Li, Na, K, Rb, Cs, Ca, Sr and Ba abundances in achondrites and in Apollo 11 lunar samples. Geochim Cosmochim Acta Suppl 1 1637-1657... 

ISOTOPES There are a total of 145 isotopes of iodine. Only one (1-127) is stable and accounts for 100% of iodine s natural abundance on Earth. All the other 146 isotopes are radioactive with half-lives ranging from a 150 nanoseconds to 1.57x10+ years. 

Iodine is the 64th most abundant element on Earth. It occurs widely over the Earth, but never in the elemental form and never in high concentrations. 

Polyolefins, like their model compounds (alkanes), are unreactive molecules. When ignited in an abundance of oxygen, polyolefins bum and produce carbon dioxide and water. Fluorine reacts with polyolefins at room temperature with explosive violence, but iodine is unreactive even at elevated temperatures. 

The abundances of krypton and xenon are determined exclusively from nucleosynthesis theory. They can be interpolated from the abundances of neighboring elements based on the observation that abundances of odd-mass-number nuclides vary smoothly with increasing mass numbers (Suess and Urey, 1956). The regular behavior of the s-process also provides a constraint (see Chapter 3). In a mature -process, the relative abundances of the stable nuclides are governed by the inverse of their neutron-capture cross-sections. Isotopes with large cross-sections have low abundance because they are easily destroyed, while the abundances of those with small cross-sections build up. Thus, one can estimate the abundances of krypton and xenon from the abundances of. v-only isotopes of neighboring elements (selenium, bromine, rubidium and strontium for krypton tellurium, iodine, cesium, and barium for xenon). 

Iodine is concentrated in humans by the thyroid gland to form the iodo-amino acid thyroxine, which is essential to normal health and development. Iodine is a rather rare element (crustal abundance 0.00003 weight %, cf. Table 1.1), so the thyroid gland has become very efficient at scavenging iodide ion. As iodine is deficient in the diet in some locations, a small amount of iodide ion is routinely added to commercial table salt ( iodized salt ). 

Low limitation of material resources for DSSCs. Oxide semiconductors such as 2, dyes, and iodine complexes are abundantly available. Although Ru resources are limited, the amount of Ru complex utilized in the DSSC is only 1 X 10 7 mol/cm2. Organic dye photosensitizers could be used rather than Ru complexes if Ru sources are limited. 

Iodine.—Iodine is perhaps the least abundant of the halogens. Although widely distributed, it always occurs in small quantities. J. H. L. Vogt12 estimates there is about O OOOl per cent, of iodine in the earth s crust—the solid matter containing about O OOOOl per cent. and the sea, O OOl per cent. A. Gautier s estimate of the iodine in the sea is about one-fifth of this. Iodine occupies the... 

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