Difference between revisions of "Inner transition element" - New World Encyclopedia

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The inner transition elements are the two series of elements that are usually shown below all the other elements in the standard view of the periodic table, but really belong to the periods 6 and 7. The two series are the lanthanides and the actinides. The lanthanide series comprises the 14 elements following lanthanum, and the actinide series similarly comprises the 14 elements following actinium. These elements, especially the actinides, were among the last to be discovered and placed in the periodic table. Chemically the elements in each series are very similar to each other. Probably the most significant use is that of Uranium (U) and Plutonium (Pu) in nuclear power generation.

**The Inner Transition Elements**

Lanthanides	58 Ce	59 Pr	60 Nd	61 Pm	62 Sm	63 Eu	64 Gd	65 Tb	66 Dy	67 Ho	68 Er	69 Tm	70 Yb	71 Lu
Actinides	90 Th	91 Pa	92 U	93 Np	94 Pu	95 Am	96 Cm	97 Bk	98 Cf	99 Es	100 Fm	101 Md	102 No	103 Lr

Definition

The definition of the inner tranisition metals is somewhat imprecise. Some include Lanthanum and Actinium to give fifteen elements in each series. From the standpoint of the electronic structure most of these elements are characterized by having partially filled f orbitals, and are also termed f-block elements. In these elements, however, the outermost d and f subshells lie close together in energy leading to some uncertainty about where to place the elements (see the periodic table showing electron configurations). Lanthanum and Actinium, have no f electrons and most clearly fit with the group 3 elements. However cerium and thorium also have no f electrons, but are considered part of these inner transition metal series. The usual arrangement is to place these elements between groups 3 and 4^[1] as is done here in the inline table.

Lanthanides

The lanthanides are named after the element lanthanum and, together with scandium and yttrium, are also sometimes referred to by the trivial name "rare earths". This name is not recommended by IUPAC, as they are neither rare in abundance (even the least abundant, lutetium, is more abundant in the Earth's crust than gold), nor are they "earths" (an obsolete term for oxides). Note that the International Union of Pure and Applied Chemistry (IUPAC) are currently recommending the name lanthanoid rather than lanthanide, as the suffix "-ide" generally indicates anions. They are charcterized by electrons in the 4f subshell.

Chemistry

The lanthanides are chemically similar to each other and useful comparison can also be made with the actinides, scandium, and yttrium. The ionic radii of the lanthanides decrease through the period — the so-called lanthanide contraction. Except for cerium (III and IV) and europium (III and II), the lanthanides occur naturally in ionic compounds as ions with a 3+ charge. As a consequence, their geochemical behaviors are a regular function of ionic radius and, therefore, atomic number. This property results in variations in the abundances of lanthanides that are used to trace natural materials through physical and chemical processes. In addition, two of the lathanides have radioactive isotopes with long half-lives (147Sm and 176Lu) that are used to date minerals and rocks from Earth, the Moon and meteorites.

Most lanthanides are widely used in lasers.

Mnemonics

To remember the sequence of the lanthanide elements, various mnemonic phrases have been used. This is the most common one:

Ladies Can't Put Nickels Properly into Slot-machines. Every Girl Tries Daily, However, Every Time You Look.

In this phrase, each word's initial letter corresponds to a lanthanide element, from Lanthanum to Lutetium.

External links

USGS Rare Earths Statistics and Information

Actinides

The actinide series, in a similar fashion to the lanthanides is named after the element actinium. They are characterized by electrons in the 5f subshell. Note that the International Union of Pure and Applied Chemistry (IUPAC) are currently recommending the name actinoid rather than actinide, as the suffix "-ide" is generally used to indicate anions.

Chemistry

The actinides display less similarity in their chemical properties than the lanthanide series, for example exhibiting a wider range of oxidation states. Initially this led to some confusion as to whether actinium, thorium and uranium should be considered d-block elements. All actinides are radioactive. Only actinium, thorium and uranium occur naturally in the earth's crust. The remaining actinides were synthesized in the 20th century by techniques such as neutron bombardment. The latter half of the series possess exceedingly short half-lives.

Phase diagram of the actinide elements.

Reference

↑ Chang, Raymond, Chemistry (9th ed.), New York: McGraw Hill, 2007.

Periodic tables

Groups: 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18

Periods: 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8

Series: Alkalis - Alkaline earths - Lanthanides - Actinides - Transition metals - Poor metals - Metalloids - Nonmetals - Halogens - Noble gases

Blocks: s-block - p-block - d-block - f-block - g-block

General subfields within the Natural sciences
Astronomy \| Biology \| Chemistry \| Earth science \| Ecology \| Physics

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[1] Chang, Raymond, Chemistry (9th ed.), New York: McGraw Hill, 2007.

[1]

@@ Line 1: / Line 1: @@
-The '''inner transition elements''' are the two series of elements that are usually shown below all the other elements in the standard view of the [[Periodic table/standard|periodic table]], but really belong to the periods 6 and 7. The two series are the '''lanthanides''' and the '''actinides'''. The '''lanthanide''' series comprises the 14 [[chemical element|element]]s following [[lanthanum]], and the '''actinide''' series similarly comprises the 14 elements following [[actinium]]. These elements, especially the actinides, were among the last to be discovered and place in the periodic table. Chemically the elements in each series are very similar to each other. Probably the most significant use is that of [[Uranium]] (U) and [[Plutonium]] (Pu) in [[nuclear power]] generation.
+The '''inner transition elements''' are the two series of elements that are usually shown below all the other elements in the standard view of the [[Periodic table/standard|periodic table]], but really belong to the periods 6 and 7. The two series are the '''lanthanides''' and the '''actinides'''. The '''lanthanide''' series comprises the 14 [[chemical element|element]]s following [[lanthanum]], and the '''actinide''' series similarly comprises the 14 elements following [[actinium]]. These elements, especially the actinides, were among the last to be discovered and placed in the periodic table. Chemically the elements in each series are very similar to each other. Probably the most significant use is that of [[Uranium]] (U) and [[Plutonium]] (Pu) in [[nuclear power]] generation.
@@ Line 44: / Line 44: @@
 == Definition ==
-The definition of the inner tranisition metals is somewhat imprecise. Some include [[Lanthanum]] and [[Actinium]] to give fifteen elements in each series. From the standpoint of the electronic structure of these elements most are characterized by having partially filled ''f'' orbitals, and are also termed [[Periodic table/block|f-block]] elements. All lanthanides except lutetium are [[f-block]] elements, corresponding to the filling of the 4f electron shell. The lanthanide series is named after lanthanum.  There are also alternative arrangements which do not include either lanthanum or lutetium.
+The definition of the inner tranisition metals is somewhat imprecise. Some include [[Lanthanum]] and [[Actinium]] to give fifteen elements in each series. From the standpoint of the electronic structure most of these elements are characterized by having partially filled ''f'' orbitals, and are also termed [[Periodic table/block|f-block]] elements. In these elements, however, the outermost ''d'' and ''f'' subshells lie close together in energy leading to some uncertainty about where to place the elements (see the periodic table showing [[Periodic table/electron configurations|electron configurations]]). [[Lanthanum]] and [[Actinium]], have no ''f'' electrons and most clearly fit with the group 3 elements. However [[cerium]] and [[thorium]] also have no ''f'' electrons, but are considered part of these inner transition metal series. The usual arrangement is to place these elements between groups 3 and 4<ref>Chang, Raymond, ''Chemistry'' (9th ed.), New York: McGraw Hill, 2007.</ref> as is done here in the [[Periodic table/wide|inline table]].
-== Terminology ==
+== Lanthanides ==
-The lanthanides, together with [[scandium]] and [[yttrium]], are also sometimes referred to by the [[trivial name]] "[[rare earth]]s", although this name is deprecated by [[IUPAC]], as they are neither rare in abundance (even the least abundant, [[lutetium]], is more abundant in the Earth's crust than [[gold]]), nor are they  "earths" (an obsolete term for [[oxide]]s).
+The lanthanides are named after the element [[lanthanum]] and, together with [[scandium]] and [[yttrium]], are also sometimes referred to by the [[trivial name]] "[[rare earth]]s". This name is not recommended by [[IUPAC]], as they are neither rare in abundance (even the least abundant, [[lutetium]], is more abundant in the Earth's crust than [[gold]]), nor are they  "earths" (an obsolete term for [[oxide]]s). Note that the [[IUPAC|International Union of Pure and Applied Chemistry (IUPAC)]] are currently recommending the name '''lanthanoid''' rather than lanthanide, as the suffix "-ide" generally indicates [[anion|anions]]. They are charcterized by electrons in the 4''f'' subshell.
-Note that the [[IUPAC|International Union of Pure and Applied Chemistry (IUPAC)]] are currently recommending the name '''lanthanoid''' rather than lanthanide, as the suffix "-ide" generally indicates [[anion|anions]].
+=== Chemistry ===
-== Chemistry ==
+The lanthanides are chemically similar to each other and useful comparison can also be made with the actinides, [[scandium]], and [[yttrium]]. The [[ionic radius|ionic radii]] of the lanthanides decrease through the period &mdash; the so-called [[lanthanide contraction]].  Except for cerium (III and IV) and europium (III and II), the lanthanides occur naturally in ionic compounds as ions with a 3+ charge. As a consequence, their geochemical behaviors are a regular function of ionic radius and, therefore, atomic number.  This property results in variations in the abundances of lanthanides that are used to trace natural materials through physical and chemical processes.  In addition, two of the lathanides have radioactive isotopes with long half-lives (147Sm and 176Lu) that are used to date minerals and rocks from Earth, the Moon and meteorites.
-Lanthanides are chemically similar to each other, to [[scandium]] and [[yttrium]]. Useful comparison can also be made with the [[actinides]], where the 5f shell is partially filled.  The lanthanides are typically placed below the main body of the periodic table in the manner of a footnote. The [[Periodic table (wide)|full-width version of the periodic table]] shows the position of the lanthanides more clearly.
-The [[ionic radius|ionic radii]] of the lanthanides decrease through the period &mdash; the so-called [[lanthanide contraction]].  Except for cerium (III and IV) and europium (III and II), the lanthanides occur as trivalent cations in nature.  As a consequence, their geochemical behaviors are a regular function of ionic radius and, therefore, atomic number.  This property results in variations in the abundances of lanthanides that are used to trace natural materials through physical and chemical processes.  In addition, two of the lathanides have radioactive isotopes with long half-lives (147Sm and 176Lu) that are used to date minerals and rocks from Earth, the Moon and meteorites.
 Most lanthanides are widely used in [[lasers]].
-== Mnemonics ==
+=== Mnemonics ===
 To remember the sequence of the lanthanide elements, various [[mnemonic]] phrases have been used. This is the most common one:
@@ Line 68: / Line 64: @@
 In this phrase, each word's initial letter corresponds to a lanthanide element, from Lanthanum to Lutetium.
-== External links ==
+=== External links ===
 *[http://minerals.usgs.gov/minerals/pubs/commodity/rare_earths/ USGS Rare Earths Statistics and Information]
-==See also==
+== Actinides ==
-*[[Group number of lanthanides and actinides]]
-*[[Rare earth element]]
-<br clear=all>
+The actinide series, in a similar fashion to the lanthanides is named after the element [[actinium]]. They are characterized by electrons in the 5''f'' subshell. Note that the [[IUPAC|International Union of Pure and Applied Chemistry (IUPAC)]] are currently recommending the name '''actinoid''' rather than actinide, as the suffix "-ide" is generally used to indicate [[anions]].
+=== Chemistry ===
-The '''actinide''' series encompasses the 15 [[chemical element]]s that lie between [[actinium]] and [[lawrencium]] on the [[periodic table]] with [[atomic number]]s 89 - 103. The actinide series is named after actinium. All actinides are [[f-block]] elements except lawrencium. There are also alternative arrangements which do not include either actinium or lawrencium in the actinide series.
+The actinides  display less similarity in their chemical properties than the lanthanide series, for example exhibiting a wider range of oxidation states. Initially this led to some confusion as to whether actinium, thorium and uranium should be considered d-block elements. All actinides are radioactive. Only actinium, thorium and uranium occur naturally in the earth's crust. The remaining actinides were synthesized in the 20th century by techniques such as neutron bombardment. The latter half of the series possess exceedingly short  [[half-life|half-lives]].
-The actinides  display less similarity in their chemical properties than the [[lanthanide]] series, for instance exhibiting a wider range of oxidation states, which initially led to confusion as to whether actinium, thorium and uranium should be considered d-block elements. All actinides are radioactive.
-Only actinium, thorium and uranium occur naturally in the earth's crust. The remaining actinides were synthesized in the 20th century by techniques such as neutron bombardment. The latter half of the series possess exceedingly short  [[half-life|half-lives]].
-The actinides are typically placed below the main body of the periodic table, in the manner of a footnote. The [[Periodic table (wide)|full-width version of the periodic table]] shows the position of the actinides more clearly.
-Note that the [[IUPAC|International Union of Pure and Applied Chemistry (IUPAC)]] are currently recommending the name '''actinoid''' rather than actinide, as the suffix "-ide" is generally used to indicate [[anions]].
   [[Image:Actinide phases.gif|left|thumb|600px|Phase diagram of the actinide elements.]]
 <br />
@@ Line 100: / Line 87: @@
 <br/>
+==Reference==
+<references />
 {{PeriodicTablesFooter}}