Atomic radii of the elements (data page)
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The atomic radius of a chemical element is a measure of the size of its atoms, usually the mean or typical distance from the nucleus to the boundary of the surrounding cloud of electrons. Since the boundary is not a well-defined physical entity, there are various non-equivalent definitions of atomic radius. Depending on the definition, the term may apply only to isolated atoms, or also to atoms in condensed matter, covalently bound in molecules, or in ionized and excited states; and its value may be obtained through experimental measurements, or computed from theoretical models. Under some definitions, the value of the radius may depend on the atom's state and context.[1]
Atomic radii vary in a predictable and explicable manner across the periodic table. For instance, the radii generally decrease along each period (row) of the table, from the alkali metals to the noble gases; and increase down each group (column). The radius increases sharply between the noble gas at the end of each period and the alkali metal at the beginning of the next period. These trends of the atomic radii (and of various other chemical and physical properties of the elements) can be explained by the electron shell theory of the atom; they provided important evidence for the development and confirmation of quantum theory.
Contents
Atomic radii
Note: All measurements given are in picometers (pm). For more recent data on covalent radii see Covalent radius.
atomic number | symbol | name | empirical † | Calculated | van der Waals | Covalent (single bond) | Covalent (triple bond) | Metallic |
---|---|---|---|---|---|---|---|---|
1 | H | hydrogen | 25 | 53 | 120 | 38 | no data | |
2 | He | helium | no data | 31 | 140 | 32 | no data | |
3 | Li | lithium | 145 | 167 | 182 | 134 | no data | 152 |
4 | Be | beryllium | 105 | 112 | 153 a | 90 | 85 | 112 |
5 | B | boron | 85 | 87 | 192 a | 82 | 73 | |
6 | C | carbon | 70 | 67 | 170 | 77 | 60 | |
7 | N | nitrogen | 65 | 56 | 155 | 75 | 54 | |
8 | O | oxygen | 60 | 48 | 152 | 73 | 53 | |
9 | F | fluorine | 50 | 42 | 147 | 71 | 53 | |
10 | Ne | neon | no data | 38 | 154 | 69 | no data | |
11 | Na | sodium | 180 | 190 | 227 | 154 | no data | 186 |
12 | Mg | magnesium | 150 | 145 | 173 | 130 | 127 | 160 |
13 | Al | aluminium | 125 | 118 | 184 a | 118 | 111 | 143 |
14 | Si | silicon | 110 | 111 | 210 | 111 | 102 | |
15 | P | phosphorus | 100 | 98 | 180 | 106 | 94 | |
16 | S | sulfur | 100 | 88 | 180 | 102 | 95 | |
17 | Cl | chlorine | 100 | 79 | 175 | 99 | 93 | |
18 | Ar | argon | 71 | 71 | 188 | 97 | 96 | |
19 | K | potassium | 220 | 243 | 275 | 196 | no data | 227 |
20 | Ca | calcium | 180 | 194 | 231 a | 174 | 133 | 197 |
21 | Sc | scandium | 160 | 184 | 211 a | 144 | 114 | 162 b |
22 | Ti | titanium | 140 | 176 | no data | 136 | 108 | 147 |
23 | V | vanadium | 135 | 171 | no data | 125 | 106 | 134 b |
24 | Cr | chromium | 140 | 166 | no data | 127 | 103 | 128 b |
25 | Mn | manganese | 140 | 161 | no data | 139 | 103 | 127 b |
26 | Fe | iron | 140 | 156 | no data | 125 | 102 | 126 b |
27 | Co | cobalt | 135 | 152 | no data | 126 | 96 | 125 b |
28 | Ni | nickel | 135 | 149 | 163 | 121 | 101 | 124 b |
29 | Cu | copper | 135 | 145 | 140 | 138 | 120 | 128 b |
30 | Zn | zinc | 135 | 142 | 139 | 131 | no data | 134 b |
31 | Ga | gallium | 130 | 136 | 187 | 126 | 121 | 135 c |
32 | Ge | germanium | 125 | 125 | 211 a | 122 | 114 | |
33 | As | arsenic | 115 | 114 | 185 | 119 | 106 | |
34 | Se | selenium | 115 | 103 | 190 | 116 | 107 | |
35 | Br | bromine | 115 | 94 | 185 | 114 | 110 | |
36 | Kr | krypton | no data | 88 | 202 | 110 | 108 | |
37 | Rb | rubidium | 235 | 265 | 303 a | 211 | no data | 248 |
38 | Sr | strontium | 200 | 219 | 249 a | 192 | 139 | 215 |
39 | Y | yttrium | 180 | 212 | no data | 162 | 124 | 180 b |
40 | Zr | zirconium | 155 | 206 | no data | 148 | 121 | 160 |
41 | Nb | niobium | 145 | 198 | no data | 137 | 116 | 146 b |
42 | Mo | molybdenum | 145 | 190 | no data | 145 | 113 | 139 b |
43 | Tc | technetium | 135 | 183 | no data | 156 | 110 | 136 b |
44 | Ru | ruthenium | 130 | 178 | no data | 126 | 103 | 134 b |
45 | Rh | rhodium | 135 | 173 | no data | 135 | 106 | 134 b |
46 | Pd | palladium | 140 | 169 | 163 | 131 | 112 | 137 b |
47 | Ag | silver | 160 | 165 | 172 | 153 | 137 | 144 b |
48 | Cd | cadmium | 155 | 161 | 158 | 148 | no data | 151 b |
49 | In | indium | 155 | 156 | 193 | 144 | 146 | 167 |
50 | Sn | tin | 145 | 145 | 217 | 141 | 132 | |
51 | Sb | antimony | 145 | 133 | 206 a | 138 | 127 | |
52 | Te | tellurium | 140 | 123 | 206 | 135 | 121 | |
53 | I | iodine | 140 | 115 | 198 | 133 | 125 | |
54 | Xe | xenon | no data | 108 | 216 | 130 | 122 | |
55 | Cs | caesium | 260 | 298 | 343 a | 225 | no data | 265 |
56 | Ba | barium | 215 | 253 | 268 a | 198 | 149 | 222 |
57 | La | lanthanum | 195 | no data | no data | 169 | 139 | 187 b |
58 | Ce | cerium | 185 | no data | no data | no data | 131 | 181.8 c |
59 | Pr | praseodymium | 185 | 247 | no data | no data | 128 | 182.4 c |
60 | Nd | neodymium | 185 | 206 | no data | no data | no data | 181.4 c |
61 | Pm | promethium | 185 | 205 | no data | no data | no data | 183.4 c |
62 | Sm | samarium | 185 | 238 | no data | no data | no data | 180.4 c |
63 | Eu | europium | 185 | 231 | no data | no data | no data | 180.4 c |
64 | Gd | gadolinium | 180 | 233 | no data | no data | 132 | 180.4 c |
65 | Tb | terbium | 175 | 225 | no data | no data | no data | 177.3 c |
66 | Dy | dysprosium | 175 | 228 | no data | no data | no data | 178.1 c |
67 | Ho | holmium | 175 | no data | no data | no data | no data | 176.2 c |
68 | Er | erbium | 175 | 226 | no data | no data | no data | 176.1 c |
69 | Tm | thulium | 175 | 222 | no data | no data | no data | 175.9 c |
70 | Yb | ytterbium | 175 | 222 | no data | no data | no data | 176 c |
71 | Lu | lutetium | 175 | 217 | no data | 160 | 131 | 173.8 c |
72 | Hf | hafnium | 155 | 208 | no data | 150 | 122 | 159 |
73 | Ta | tantalum | 145 | 200 | no data | 138 | 119 | 146 b |
74 | W | tungsten | 135 | 193 | no data | 146 | 115 | 139 b |
75 | Re | rhenium | 135 | 188 | no data | 159 | 110 | 137 b |
76 | Os | osmium | 130 | 185 | no data | 128 | 109 | 135 b |
77 | Ir | iridium | 135 | 180 | no data | 137 | 107 | 135.5 b |
78 | Pt | platinum | 135 | 177 | 175 | 128 | 110 | 138.5 b |
79 | Au | gold | 135 | 174 | 166 | 144 | 123 | 144 b |
80 | Hg | mercury | 150 | 171 | 155 | 149 | no data | 151 b |
81 | Tl | thallium | 190 | 156 | 196 | 148 | 150 | 170 |
82 | Pb | lead | 180 | 154 | 202 | 147 | 137 | |
83 | Bi | bismuth | 160 | 143 | 207 a | 146 | 135 | |
84 | Po | polonium | 190 | 135 | 197 a | no data | 129 | |
85 | At | astatine | no data | no data | 202 a | no data | 138 | |
86 | Rn | radon | no data | 120 | 220 a | 145 | 133 | |
87 | Fr | francium | no data | no data | 348 a | no data | no data | no data |
88 | Ra | radium | 215 | no data | 283 a | no data | 159 | no data |
89 | Ac | actinium | 195 | no data | no data | no data | 140 | |
90 | Th | thorium | 180 | no data | no data | no data | 136 | 179 b |
91 | Pa | protactinium | 180 | no data | no data | no data | 129 | 163 d |
92 | U | uranium | 175 | no data | 186 | no data | 118 | 156 e |
93 | Np | neptunium | 175 | no data | no data | no data | 116 | 155 e |
94 | Pu | plutonium | 175 | no data | no data | no data | no data | 159 e |
95 | Am | americium | 175 | no data | no data | no data | no data | 173 b |
96 | Cm | curium | no data | no data | no data | no data | no data | 174 b |
97 | Bk | berkelium | no data | no data | no data | no data | no data | 170 b |
98 | Cf | californium | no data | no data | no data | no data | no data | 186+/- 2 b |
99 | Es | einsteinium | no data | no data | no data | no data | no data | 186+/- 2 b |
100 | Fm | fermium | no data | no data | no data | no data | no data | no data |
101 | Md | mendelevium | no data | no data | no data | no data | no data | no data |
102 | No | nobelium | no data | no data | no data | no data | no data | no data |
103 | Lr | lawrencium | no data | no data | no data | no data | no data | no data |
104 | Rf | rutherfordium | no data | no data | no data | no data | 131 | no data |
105 | Db | dubnium | no data | no data | no data | no data | 126 | no data |
106 | Sg | seaborgium | no data | no data | no data | no data | 121 | no data |
107 | Bh | bohrium | no data | no data | no data | no data | 119 | no data |
108 | Hs | hassium | no data | no data | no data | no data | 118 | no data |
109 | Mt | meitnerium | no data | no data | no data | no data | 113 | no data |
110 | Ds | darmstadtium | no data | no data | no data | no data | 112 | no data |
111 | Rg | roentgenium | no data | no data | no data | no data | 118 | no data |
112 | Cn | copernicium | no data | no data | no data | no data | 130 | no data |
113 | Uut | ununtrium | no data | no data | no data | no data | no data | no data |
114 | Fl | flerovium | no data | no data | no data | no data | no data | no data |
115 | Uup | ununpentium | no data | no data | no data | no data | no data | no data |
116 | Lv | livermorium | no data | no data | no data | no data | no data | no data |
117 | Uus | ununseptium | no data | no data | no data | no data | no data | no data |
118 | Uuo | ununoctium | no data | no data | no data | no data | no data | no data |
Notes
- The radius of an atom is not a uniquely defined property and depends on the definition. Data derived from other sources with different assumptions cannot be compared.
-
† to an accuracy of about 5 pm
-
(a) These radii are taken from M. Mantina, A.C. Chamberlin, R. Valero, C.J. Cramer, and D.G. Truhlar, J. Phys. Chem. 2009, 113, 5806.
-
(b) 12 coordinate
-
(c) gallium has an anomalous crystal structure
-
(d) 10 coordinate
See also
- Atomic radius
- Covalent radius (Single-, double- and triple-bond radii, up to the superheavy elements.)
- Ionic Radius
References
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Data is as quoted at http://www.webelements.com/ from these sources:
Atomic radius (empirical)
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Atomic radius (calculated)
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Van der Waals radius
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Covalent radii (single bond)
More recent data can be found in Covalent radius. The above values are based on
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Triple-bond covalent radii
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- Triple-Bond Covalent Radii Table online
Metallic radius
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