Metalloid
A metalloid or semimetal is a chemical element. Metalloids are elements that have the properties of both metal and non-metal elements. It might be shiny, but brittle. It might be dull, but conduct electricity.
The most common semimetal is silicon. Silicon has electrical conductivity between metals and nonmetals. It is a semiconductor.
| Group | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | ||
| Period | ||||||||||||||||||||
| 1 | 1 H |
2 He | ||||||||||||||||||
| 2 | 3 Li |
4 Be |
5 B |
6 C |
7 N |
8 O |
9 F |
10 Ne | ||||||||||||
| 3 | 11 Na |
12 Mg |
13 Al |
14 Si |
15 P |
16 S |
17 Cl |
18 Ar | ||||||||||||
| 4 | 19 K |
20 Ca |
21 Sc |
22 Ti |
23 V |
24 Cr |
25 Mn |
26 Fe |
27 Co |
28 Ni |
29 Cu |
30 Zn |
31 Ga |
32 Ge |
33 As |
34 Se |
35 Br |
36 Kr | ||
| 5 | 37 Rb |
38 Sr |
39 Y |
40 Zr |
41 Nb |
42 Mo |
43 Tc |
44 Ru |
45 Rh |
46 Pd |
47 Ag |
48 Cd |
49 In |
50 Sn |
51 Sb |
52 Te |
53 I |
54 Xe | ||
| 6 | 55 Cs |
56 Ba |
* |
71 Lu |
72 Hf |
73 Ta |
74 W |
75 Re |
76 Os |
77 Ir |
78 Pt |
79 Au |
80 Hg |
81 Tl |
82 Pb |
83 Bi |
84 Po |
85 At |
86 Rn | |
| 7 | 87 Fr |
88 Ra |
* * |
103 Lr |
104 Rf |
105 Db |
106 Sg |
107 Bh |
108 Hs |
109 Mt |
110 Ds |
111 Rg |
112 Cn |
113 Nh |
114 Fl |
115 Mc |
116 Lv |
117 Ts |
118 Og | |
| * Lanthanides | 57 La |
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 | ||||||
| ** Actinides | 89 Ac |
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 | ||||||
| Metals | Metalloids | Nonmetals |
An approximate way to classify metalloids is to look at the Periodic Table of elements. See the double diagonal line: top left Boron and Aluminium, bottom right Polonium and Astatine. Those diagonals are the metalloids. Some metalloids are not semimetals, and some semimetals are not metalloids.
Gallery
Antimony, a semimetal, can be found naturally in the earth.
Arsenic is another semimetal that is very toxic.
Tellurium in a bottle. Tellurium sometimes is found naturally.
Germanium in a tube. Germanium can be used to make semiconductors. Silicon is used more.
Silicon crystal. Silicon is used to make semiconductors.
Boron in a tube. Boron is very hard.
Metalloid Media
Copper-germanium alloy pellets, likely ~84% Cu; 16% Ge. When combined with silver the result is a tarnish resistant sterling silver. Also shown are two silver pellets.
Arsenic trioxide or white arsenic, one of the most toxic and prevalent forms of arsenic. The antileukaemic properties of white arsenic were first reported in 1878.
Optical fibers, usually made of pure silicon dioxide glass, with additives such as boron trioxide or germanium dioxide for increased sensitivity
Archaic blue light signal, fuelled by a mixture of sodium nitrate, sulfur, and (red) arsenic trisulfide
Boron, shown here in the form of its β-rhombohedral phase (its most thermodynamically stable allotrope)
Arsenic, sealed in a container to prevent tarnishing
