ランタノイド 化学特性,用途語,生産方法
解説
57番元素ランタンLaから71番元素ルテチウムLuまでの15元素の総称．別名ランタニド．ランタニドは本来ランタンに似た元素という意味をもち，古く58番元素セリウムCeから71番元素Luまでをまとめてこのようによんでいた．その後，これらの元素の電子構造，化学的性質の類似などから57番元素Laを含めてよぶことも多くなり，これらの混乱を避けるため，ランタノン(lanthanons)，ランタン系列(lanthanum series)などの名称も提案された．しかし，これらもランタンを含めるか，含めないかなどの混乱を避けるにはいたらなかった．そのため最初のIUPAC命名法規則(1957)では，57番元素Laから71番元素Luまでをランタン系列，58番元素Ceから71番元素Luまでをランタニドとしたが，1970年規則ではLaからLuまでを含めてランタノイドに統一され，1990年規則では改めてランタニドの使用も認められた．
定義
A group of elements whose
electronic configurations display back filling
of the 4f-level. There is a maximum of
14 electrons in an f-orbital. The element
lanthanum itself has no f-electrons (La
[Xe]5d
16s
2) and is thus strictly not a lanthanoid,
but it is included by convention,
thus giving a closely related series of 15 elements.
Excluding lanthanum, the elements
all have 4f
x6s
2 configurations but
gadolinium and lutecium have an additional
5d1 electron.
The characteristic oxidation state is
M
3+ and the great similarity in the size of
the ions leads to a very close similarity of
chemical properties and hence to great difficulties
of separation using conventional
methods. Chromatographic and solvent solventextraction
methods have been specially developed
for the lanthanoids.
工業用途
The lanthanoid series consists of 14 elements (cerium to lutetium) and they are also called f-block metals,
as the valence shell of lanthanoids contains 4f orbitals. Lanthanoids are named after the element lanthanum
(La), which itself is a d-block metal. Nevertheless, because of its very similar chemical behaviour, lanthanum
is often also classified as a lanthanoid. The term rare earth metals describes the lanthanoid series together
with lanthanum (La), scandium (Sc) and yttrium (Y).
Mostly, lanthanoids are used in the production of batteries, lasers and other technological devices. Some
lanthanoids salts, such as the salts of lanthanum, cerium and gadolinium (highlighted in Figure 9.1), are
increasingly used in a clinical setting, for example, as a phosphate binder in the treatment of renal osteodystrophy
or as MRI (magnetic resonance imaging) contrast agents (CAs).
ランタノイド 上流と下流の製品情報
原材料
準備製品