Metalloid

Metalloid is a term used in chemistry when classifying the chemical elements. On the basis of their general physical and chemical properties, nearly every element in the periodic table can be termed either a metal or a nonmetal. A few elements with intermediate properties are, however, referred to as metalloids. (In Greek metallon = metal and eidos = sort)

There is no rigorous definition of the term, but the following properties are usually considered characteristic of metalloids:

• metalloids often form amphoteric oxides.
• metalloids often behave as semiconductors (B,Si,Ge) to semimetals (eg. Sb).

The concepts of metalloid and semiconductor should not be confused. Metalloid refers to the properties of certain elements in relation to the periodic table. Semiconductor refers to the physical properties of materials (including alloys, compounds) and there is only partial overlap between the two.

The following elements are generally considered metalloids:

• Boron (B)
• Silicon (Si)
• Germanium (Ge)
• Arsenic (As)
• Antimony (Sb)
• Tellurium (Te)
• Polonium (Po)

Some allotropes of elements exhibit more pronounced metal, metalloid or non-metal behavior than others. For example, for the element carbon, its diamond allotrope is clearly non-metallic, but the graphite allotrope displays limited electric conductivity more characteristic of a metalloid. Phosphorus, tin, selenium and bismuth also have allotropes that display borderline behavior.

In the standard layout of the periodic table, metalloids occur along the diagonal line through the p block from boron to polonium. Elements to the upper right of this line display increasing nonmetallic behavior; elements to the lower left display increasing metallic behavior. This line is called the "stair-step" or "staircase." The poor metals are to the left and down and the nonmetals are to the right and up.

13	14	15	16	17
B Boron	C Carbon	N Nitrogen	O Oxygen	F Fluorine
Al Aluminium	Si Silicon	P Phosphorus	S Sulfur	Cl Chlorine
Ga Gallium	Ge Germanium	As Arsenic	Se Selenium	Br Bromine
In Indium	Sn Tin	Sb Antimony	Te Tellurium	I Iodine
Tl Thallium	Pb Lead	Bi Bismuth	Po Polonium	At Astatine

See also

• Boron

External links

Periodic tables

Standard table | Vertical table | Table with names | Names and atomic masses (large) | Names and atomic masses (small) | Names and atomic masses (text only) | Inline F-block | Elements to 218 | Electron configurations | Metals and non metals | Table by blocks | List of elements by name

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

Credits

New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

• Metalloid  ^history

The history of this article since it was imported to New World Encyclopedia:

• History of "Metalloid"

Note: Some restrictions may apply to use of individual images which are separately licensed.