The most important source of the lanthanides is monazite, a heavy dark sand found in Brazil, India, Australia, South Africa, and the United States. The composition of monazite varies depending on its location, but it generally contains about 50 percent of lanthanide compounds by weight. Lanthanides or more precisely lanthanides ions are coloured mainly because of their partly filled f orbitals.
It is also possible for some elements, such as Tm, to be used as portable x-ray sources. Other elements, such as Eu, can be used as radiation sources. Introduction The Lanthanides were first discovered in when a unusual black mineral was found in Ytterby, Sweden. Adoption of coordination numbers greater than 6 usually in compounds Tendency to decreasing coordination number across the series A preference for more electronegative elements such as O or F binding Very small crystal-field effects Little dependence on ligands Ionic complexes undergo rapid ligand-exchange.
Electron Configuration Similarly, the Lanthanides have similarities in their electron configuration, which explains most of the physical similarities. Properties and Chemical Reactions One property of the Lanthanides that affect how they will react with other elements is called the basicity.
Metals and their Alloys The metals have a silvery shine when freshly cut. Periodic Trends: Size The size of the atomic and ionic radii is determined by both the nuclear charge and by the number of electrons that are in the electronic shells. Color and Light Absorbance The color that a substance appears is the color that is reflected by the substance. Occurrence in Nature Each known Lanthanide mineral contains all the members of the series. The three main mineral sources are the following: Monazite: contains mostly the lighter Lanthanides.
The commercial mining of monazite sands in the United States is centered in Florida and the Carolinas Xenotime: contains mostly the heavier Lanthanides Euxenite: contains a fairly even distribution of the Lanthanides In all the ores, the atoms with a even atomic number are more abundant. The Oddo-Harkins Rule The abundance of elements with an even atomic number is greater than the abundance of elements with an odd atomic number.
Applications Metals and Alloys The pure metals of the Lanthanides have little use. Non-nuclear The Lanthanides can also be used for ceramic purposes. Nuclear Like the Actinides, the Lanthanides can be used for nuclear purposes.
Practice Problems Which elements are considered to be Lanthanides? How do the Lanthanides react with oxygen? What causes the Lanthanide Contraction? Why do Lanthanides exhibit strong electromagnetic and light properties? What do the Lanthanides have in common with the Noble Gases? Answers Elements Lanthanum 57 through Lutetium 71 on the periodic table are considered to be Lanthanides. Lanthanides tend to react with oxygen to form oxides. The reaction at room temperature can be slow while heat can cause the reaction to happen rapidly.
The Lanthanide Contraction refers to the decrease in atomic size of the elements in which electrons fill the f-subshell. Since the f sub-shell is not shielded, the atomic size will decrease as the nuclear charge still increases. Lanthanides exhibit strong electromagnetic and light properties because of the presence of unpaired electrons in the f-orbitals. The majority of the Lanthanides are paramagnetic, which means that they have strong magnetic fields.
Both the Lanthanides and Noble Gases tend to bind with more electronegative atoms, such as Oxygen or Fluorine. References Petrucci, Hardwood, Herring. New Jersey: Macmillan Publishing Company, Moeller, Therald. The Chemistry of the Lanthanides.
New York: Reinhold Publishing Corporation, Cotton, Simon. Facebook Facebook Twitter Twitter. Key Takeaways: Lanthanide The lanthanides are a group of 15 chemical elements, with atomic numbers 57 through All of these elements have one valence electron in the 5d shell.
The elements share properties in common with the first element in the group -- lanthanum. The lanthanides are reactive, silver-colored metals. Although the lanthanides are sometimes called the rare earths, the elements are not particularly rare. However, they are difficult to separate from one another. Featured Video. Cite this Article Format. Helmenstine, Anne Marie, Ph. Lanthanides Properties and Elements. Transition Metals: List and Properties.
Properties and Reactions of the Actinide Series of Elements. Metallic Character: Properties and Trends. Element Families of the Periodic Table. Periodic Table Definition in Chemistry. Metals Versus Nonmetals - Comparing Properties. Your Privacy Rights.
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