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McGraw Hill Financial, Inc. is an American publicly traded corporation headquartered in Rockefeller Center in New York City. Its primary areas of business are financial, publishing, and business services.
A chemical element, Fr, atomic number 87, an alkali metal element falling below cesium in group 1 of the periodic table. Distinguished by nuclear instability, francium exists only in short-lived radioactive forms, the most durable of which has a half-life of 21 min. The chief isotope of francium is actinium-K, an isotope of mass 223, which arises from the radioactive decay of the element actinium. From the properties of the known isotopes, it is reasonably certain that no long-lived form of element 87 will ever be found in nature or synthesized artificially.
Industry:Science
A chemical element, Ga, atomic number 31, atomic weight 69.72. Gallium is a member of group 13 and the fourth period of the periodic table (IUPAC).
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A chemical element, Hg, atomic number 80 and atomic weight 200.59. Mercury is a silverwhite liquid at room temperature (melting point −38.89°C or −37.46°F); it boils at 357.25°C (675.05°F) under atmospheric pressure. It is a noble metal that is soluble only in oxidizing solutions. Solid mercury is as soft as lead. The metal and its compounds are very toxic. With some metals (gold, silver, platinum, uranium, copper, lead, sodium, and potassium, for example) mercury forms solutions called amalgams.
Industry:Science
A chemical element, Ho, atomic number 67, atomic weight 164.93, a metallic element belonging to the rare-earth group. The stable isotope <sup>165</sup>Ho makes up 100% of the naturally occurring element. The metal is paramagnetic, but as the temperature is lowered, it changes to antiferromagnetic and then to the ferromagnetic system.
Industry:Science
A chemical element, In, atomic number 49, a member of group 13 and the fifth period of the periodic table. Indium has a relative atomic weight of 114.82. Indium occurs in the Earth's crust to the extent of about 0.000001% and is normally found in concentrations of 0.1% or less. It is widely distributed in many ores and minerals but is largely recovered from the flue dusts and residues of zinc-processing operations.
Industry:Science
A chemical element, Ir, atomic number 77, relative atomic weight 192.22. Iridium is a transition metal and shares similarities with rhodium as well as the other platinum metals, including palladium, platinum, ruthenium, and osmium. The atom in the gas phase has the electronic configuration 1<i>s</i><sup>2</sup>, 2<i>s</i><sup>2</sup>, 2<i>p</i><sup>6</sup>, 3<i>s</i><sup>2</sup>, 3<i>p</i><sup>6</sup>, 3<i>d</i><sup>10</sup>, 4<i>s</i><sup>2</sup>, 4<i>p</i><sup>6</sup> 4<i>d</i><sup>10</sup>, 4<i>f</i><sup>14</sup>, 5<i>s</i><sup>2</sup>, 5<i>p</i><sup>6</sup>, 5<i>d</i><sup>7</sup>, 6<i>s</i><sup>2</sup>. The ionic radius for Ir<sup>3+</sup> is 0.068 nanometer and its metallic radius is 0.1357 nm. Metallic iridium is slightly less dense than osmium, which is the densest of all the elements.
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A chemical element, K, atomic number 19, and atomic weight 39.102. It stands in the middle of the alkali metal family, below sodium and above rubidium. This lightweight, soft, low-melting, reactive metal (see <b>table</b>) is very similar to sodium in its behavior in metallic forms.
Industry:Science
A chemical element, La, atomic number 57, atomic weight 138.91. Lanthanum, the second most abundant element in the rare-earth group, is a metal. The naturally occurring element is made up of the isotopes <sup>138</sup>La, 0.089%, and <sup>139</sup>La, 99.91%. <sup>138</sup>La is a radioactive positron emitter with a half-life of 1.1 × 10<sup>11</sup> years. The element was discovered in 1839 by C. G. Mosander and occurs associated with other rare earths in monazite, bastnasite, and other minerals. It is one of the radioactive products of the fission of uranium, thorium, or plutonium. Lanthanum is the most basic of the rare earths and can be separated rapidly from other members of the rare-earth series by fractional crystallization. Considerable quantities of it are separated commercially, since it is an important ingredient in glass manufacture. Lanthanum imparts a high refractive index to the glass and is used in the manufacture of expensive lenses. The metal is readily attacked in air and is rapidly converted to a white powder. Lanthanum becomes a superconductor below about 6 K (−449°F) in both the hexagonal and face-centered crystal forms.
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A chemical element, Li, atomic number 3, and atomic weight 6.939. Lithium heads the alkali metal family in the periodic table. In nature it is a mixture of the isotopes <sup>6</sup>Li and <sup>7</sup>Li. Lithium, the lightest solid element, is a soft, low-melting, reactive metal. In many physical and chemical properties it resembles the alkaline-earth metals as much as, or more than, it does the alkali metals.
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A chemical element, Lu, atomic number 71, atomic weight 174.97, a very rare metal and the heaviest member of the rare-earth group. The naturally occurring element is made up of the stable isotope <sup>175</sup>Lu, 97.41%, and the long-life β-emitter <sup>176</sup>Lu with a half-life of 2.1 × 10<sup>10</sup> years.
Industry:Science
