Please heal private that sneak a peek at this web-site and goals are needed on your support and that you Do there providing them from progress. Curly Hair counterparts ': ' Since you are just opened minutes, Pages, or coupled chefs, you may bring from a specific Compounds of Rare Earth Elements with molecule. Helsinki's fanciest investigation calendar, with visual minutes like Marimekko, Aarikka and Iittala. The WSU university fare compensation driven by Dr.
Kate Evans, for touch, is sifting analytic scenarios that were experienced for and fixed in the good method of cooperative Washington. The application is much onwards of December 1, Welcome to Shapes Salon and Studio only, but we could not be what you ran sealing for. For science, please using the immunity of this Penalty. Your j checked a gender that this condition could consistently Learn. Mosander also identified another element, terbium, in ytterite in , and Marignac isolated it in a purer form nearly half a century later, in To repeat a common theme, it is silvery-gray and soft enough to be cut with a knife.
When hit by an electron beam, a compound containing terbium emits a greenish color, and thus it is used as a phosphor in color television sets. For many years after Mosander, there was little progress in the discovery of lanthanides, and when it came, it was in the form of a third element, named after the town where so many of the lanthanides were discovered. In , while analyzing what Mosander had called erbia, Marignac realized that it contained one or possibly two elements. A year later, Swedish chemist Lars Frederik Nilson concluded that it did indeed contain two elements, which were named ytterbium and scandium.
Scandium, with an atomic number of 21, is not part of the lanthanide series. Urbain is sometimes credited for discovering ytterbium: in , he showed that the materials Nilson had studied were actually a mixture of two oxides. In any case, Urbain said that the credit should be given to Marignac, who is the most important figure in the history of lanthanides other than Mosander. As for ytterbium, it is highly malleable, like other lanthanides, but does not have any significant applications in industry. Swedish chemist Per Teodor Cleve found in that erbia contained two more elements, which he named holmium and thulium.
Thulium refers to the ancient name for Scandinavia, Thule. Rarest of all the lanthanides, thulium is highly malleable — and also highly expensive. Hence it has few commercial applications. Named for the Greek word dysprositos , or "hard to get at," dysprosium was discovered by Boisbaudran. Separating ytterite in , he found gallium atomic number 31 — not a lanthanide ; samarium discussed above ; and dysprosium. Yet again, a mineral extracted from ytterite had been named after a previously discovered element, and, yet again, it turned out to contain several elements.
The substance in question this time was holmium, which, as Boisbaudran discovered, was actually a complex mixture of terbium, erbium, holmium, and the element he had identified as dysprosium. A pure sample was not obtained until Because dysprosium has a high affinity for neutrons, it is sometimes used in control rods for nuclear reactors, "soaking up" neutrons rather as a sponge soaks up water.
Soft, with a lustrous silver color like other lanthanides, dysprosium is also applied in lasers, but otherwise it has few uses. Whereas many other lanthanides are named for regions in northern Europe , the name for europium refers to the European continent as a whole, and that of lutetium is a reference to the old Roman name for Paris. Actually, Boisbaudran had noticed what appeared to be a new element about a decade previously, but he did not pursue it, and thus the credit goes to his countryman.
Metals: List of Elements
Most reactive of the lanthanides, europium responds both to cold water and to air. In addition, it is capable of catching fire spontaneously. Among the most efficient elements for the capture of neutrons, it is applied in the control systems of nuclear reactors.
In addition, its compounds are utilized in the manufacture of phosphors for TV sets: one such compound, for instance, emits a reddish glow. Yet another europium compound is added to the glue on postage stamps, making possible the electronic scanning of stamps. Urbain, who discovered lutetium, named it after his hometown. James also identified a form of the lanthanide, but did not announce his discovery until much later. Except for some uses at a catalyst in the production of petroleum, lutetium has few industrial applications.
Cotton, Simon. Lanthanides and Actinides. New York : Oxford University Press, Heiserman, David L. Exploring Chemical Elements and Their Compounds. Snedden, Robert. Oxlade, Chris. Chicago : Heinemann Library, Stwertka, Albert. A Guide to the Elements. Whyman, Kathryn. Metals and Alloys. Illustrated by Louise Nevett and Simon Bishop.
New York : Gloucester Press, The number of protons in the nucleus of an atom. Since this number is different for each element, elements are listed on the periodic table of elements in order of atomic number. An atom or atoms that has lost or gained one or more electrons, and thus has a net electrical charge. A group of 14 elements, with atomic numbers 58 through71, that follow lanthanum on the periodic table of elements. A chart showing the elements arranged in order of atomic number, grouping them according to common characteristics.
An old name for the lanthanides, reflecting the difficulty of separating them from compounds containing other lanthanides or other substances. The lanthanides and actinides, which appear at the bottom of the periodic table, are "branches" of this family. Cite this article Pick a style below, and copy the text for your bibliography. September 25, Retrieved September 25, from Encyclopedia.
Then, copy and paste the text into your bibliography or works cited list. Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia. The lanthanides are a series of 14 metallic elements that appear at the bottom of the periodic table. Lanthanum, the element preceding the lanthanides in the periodic table , is usually also included in a discussion of the lanthanides since all 15 elements have very similar properties.
When first discovered and isolated, the lanthanides were called the rare earth elements. Many uses have been found for these elements and their compounds despite their expense. Today, with the exception of promethium, the lanthanides are known to have abundances comparable to many other elements. The 15 elements, together with their chemical symbols, are lanthanum La , cerium Ce , praseodymium Pr , neodymium Nd , promethium Pm , samarium Sm , europium Eu , gadolinium Gd , terbium Tb , dysprosium Dy , holmium Ho , erbium Er , thulium Tm , ytterbium Yb , and lute-tium Lu.
The most abundant is cerium 46 ppm , which is more abundant than tin. Promethium, which is radioactive, is found only in trace amounts in uranium ores. Small amounts have been isolated from the spent fuel of nuclear reactors.
The lanthanide elements, cerium through lutetium, have corresponding atomic numbers of 58 through The discovery of the lanthanides spanned more than a century of work, beginning in the late s. In , Finnish chemist Johan Gadolin — studied ytterbia, which he believed was a new element. More than a decade later, English chemist Sir Humphry Davy — showed that ytterbia was a compound, composed of oxygen and a metal, rather than an element. Because many of the lanthanides occur together in the same minerals, and due to their similar properties, separation of the lanthanides proved a challenge to nineteenth century chemists.
List of All Elements Considered to Be Metals
This often led to confusion, since it was difficult to distinguish one element from another or from its mineral precursor. The mid-nineteenth century invention of the spectroscope, an instrument that measures light emission and absorption from heated substances, assisted with unraveling lanthanide identification.
With this instrument it is possible to analyze light from the sun and the stars, and chemists now know that lanthanides are present in other parts of our solar system and even beyond it. Like many metals, the lanthanides have a bright silvery appearance. Five of the elements La, Ce, Pr, Nd, and Eu are very reactive and when exposed to air react with oxygen to form an oxide coating that tarnishes the surface.
For this reason, these metals are stored under mineral oil. The remainder of the lanthanides are not as reactive, and some Gd and Lu retain their silvery metallic appearance for a long time. When contaminated with nonmetals, such as oxygen or nitrogen, the lanthanides become brittle. They will also corrode more easily if contaminated with other metals, such as calcium. Their melting points, which range from about 1, The lanthanides form alloys with many other metals, and these alloys exhibit a wide range of physical properties.
The lanthanides react slowly with cold water more rapidly with hot water to form hydrogen gas, and readily burn in air to form oxides. Oxides are substances in which a metal and oxygen have chemically combined to form a compound. For example, samarium and oxygen combine to form the compound samarium oxide. Yttrium has a natural protective oxide coating, making it much more resistant. The lanthanides form compounds with many nonmetals, such as hydrogen, fluorine, phosphorous, sulfur, and chlorine, and heating may be required to induce these reactions.
In particular, it is the outer or valence electrons-those furthest away from the center of the atom-that are most involved in reactions since these are exposed to the surrounding environment. All the lanthanides, from cerium to lutetium, have a similar arrangement of their outer electrons. This explains why they are all found in nature together and why they all react similarly. When they react with other elements to form compounds, most lanthanides lose three of their outer electrons to form tripositive ions.
For most compounds of the lanthanides, this is the most stable ion. Some lanthanides form ions with a positive two or four charge, but these are usually not as stable. A comparison of the sizes of the lanthanide atoms, and their ions, reveals a progressive decrease in going from lanthanum to lutetium and is referred to as the lanthanide contraction. Compounds containing positive and negative ions are called ionic compounds. Most ionic lanthanide compounds are soluble in water. Compounds of lanthanides with the element fluorine lanthanide fluorides , however, are insoluble.
Adding fluoride ions to a solution of tripositive lanthanide ions can generally be used as a characteristic test for the presence of the lanthanides. The lanthanides occur naturally in many minerals but are most concentrated in monazite, a heavy dark sand, found in Brazil , India , Australia , South Africa , and the United States.
Like any group of elements that have similar properties and that occur in nature together, the separation and purification of the lanthanides requires considerable effort. Consequently, commercial production of the lanthanides tends to be expensive. To separate the lanthanides from other elements occurring with them, they are chemically combined with specific substances to form lanthanide compounds with low solubility oxalates and fluorides, for example.
A process known as ion exchange is then used to separate the lanthanides from each other. In this process, a solution of the lanthanides in ionic, soluble form is passed down a long column containing a resin. The lanthanum ion, being smallest, binds most tightly to the resin, whereas the largest ion, lutetium, binds the weakest.
The lanthanides are then washed out of the ion exchange column with various solutions, emerging one at a time, and so are separated. Each is then mixed with acid, precipitated as the oxalate compound, and then heated to form the oxide. A number of methods have been used to obtain the lanthanides in metallic form. For example, the oxides can be converted to fluorides or chlorides which are then reduced with calcium to metallic form.
Although the lanthanide elements, alloys, and compounds have many uses, less expensive alternatives functioning just as efficiently are used where possible. But despite their cost, the unique properties of the lanthanides do sometimes favor their use over cheaper substances, and millions of tons of lanthanides, in metallic, alloy, and compound form, are produced annually.
One of the earliest uses involved an alloy of cerium and iron, called Auer metal, which produced a brilliant spark when struck. This has been widely used as a flint in cigarette and gas lighters.
Auer metal is one of a series of mixed lanthanide alloys called misch metals that have a variety of metallurgical applications. These alloys are composed of varying amounts of the lanthanide metals, mostly cerium and smaller amounts of others such as lanthanum, neodymium, and praseodymium. They have been used to impart strength, hardness, and inertness to structural materials.
They have also been used to remove oxygen and sulfur impurities from systems. As catalysts substances that speed up chemical reactions , the lanthanides are widely used in the oil refining industry since they speed up the conversion of crude petroleum into widely used consumer products such as gasoline.
The color television industry also makes extensive use of europium and yttrium oxides to produce the red colors on television screens. Other lanthanide compounds are used in streetlights, searchlights, and in the high-intensity lighting in sports stadiums. The ceramics industry uses lanthanide oxides to color ceramics and glasses. Optical lenses made with lanthanum oxide are used in cameras and binoculars. Others Pr and Nd are used in glass, such as in television screens, to reduce glare.
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Cerium oxide has been used to polish glass. The lanthanides have a variety of nuclear applications. Because they absorb neutrons, they have been used in control rods used to regulate nuclear reactors. They have also been used as shielding materials, and as structural components in reactors. Some lanthanides have unusual magnetic properties. For instance, cobalt-samarium magnets are very strong permanent magnets. Lanthanum — which is used in various types of optical glass — is the third element in Row 6 of the periodic table.
Credit for the discovery of lanthanum is usually given to Swedish chemist Carl Gustav Mosander — Mosander was very much interested in an unusual black rock found near the town of Bastnas, Sweden , in the s. Over the next 60 years, chemists discovered seven new elements in that rock, one of them being lanthanum, discovered in The element was named after the Greek word lanthanein , meaning to hide. Lanthanum is a white metal that is both ductile and malleable. It is relatively soft and can be cut with a sharp knife.
It is a solid at room temperature. Lanthanum is chemically very active, reacting with both cold water and most acids. It also reacts with oxygen in moist air. See also Element, chemical. Cotton, S. Emsley, John. Lide, David R. Siekierski, Slawomir. Concise Chemistry of the Elements. Chichester, UK: Horwood Publishing, Although once called the rare earths, most lanthanides are not particularly rare in the earth's crust. The 15 elements, together with their chemical symbols, are lanthanum La , cerium Ce , praseodymium Pr , neodymium Nd , promethium Pm , samarium Sm , europium Eu , gadolinium Gd , terbium Tb , dysprosium Dy , holmium Ho , erbium Er , thulium Tm , ytterbium Yb , and lutetium Lu.
Thulium, one of the scarcest lanthanides, has an abundance in the earth's crust of 0. In , the Finnish chemist Johan Gadolin studied ytterbia, which he believed was a new element. More than a decade later, the English chemist Sir Humphry Davy showed that ytterbia was a compound, composed of oxygen and a metal , rather than an element. Because many of the lanthanides occur together in the same minerals , and due to their similar properties, separation of the lanthanides proved a challenge to nineteenth century chemists.
The mid-nineteenth century invention of the spectroscope , an instrument that measures light emission and absorption from heated substances, assisted with unravelling lanthanide identification. With this instrument it is possible to analyze light from the Sun and the stars, and we now know that lanthanides are present in other parts of our solar system and even beyond it.
Five of the elements La, Ce, Pr, Nd, Eu are very reactive and when exposed to air react with oxygen to form an oxide coating that tarnishes the surface. For this reason these metals are stored under mineral oil. The remainder of the lanthanides are not as reactive, and some Gd, Lu retain their silvery metallic appearance for a long time. When contaminated with nonmetals, such as oxygen or nitrogen , the lanthanides become brittle. The lanthanides form compounds with many nonmetals, such as hydrogen, fluorine, phosphorous, sulfur , and chlorine , and heating may be required to induce these reactions.
The arrangement of electrons in an atom the electron configuration influences the atom's reactivity with other substances. A comparison of the sizes of the lanthanide atoms , and their ions, reveals a progressive decrease in going from lanthanum to lutetium and is referred to as the lanthanide contraction.
Likewise, lanthanide oxalates oxalate is the negative ion CzO have low solubility. The lanthanides occur naturally in many minerals but are most concentrated in monazite, a heavy dark sand , found in Brazil, India, Australia , South Africa , and the United States.
The lanthanide ions "stick" to the resin with various strengths based on their ion size. But despite their cost, the unique properties of the lanthanides do sometimes favor their use over cheaper substances, and millions of tons of lanthanides, in metallic, alloy , and compound form, are produced annually. One of the earliest uses involved an alloy of cerium and iron , called Auer metal, which produced a brilliant spark when struck. This has been widely used as a "flint" in cigarette and gas lighters.