Atomic radii of the elements (data page)


The atomic radius of a chemical element is the distance from the centre of the nucleus to the outermost shell of the electron. 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.
Atomic radii vary in a predictable and explicable manner across the periodic table. For instance, the radii generally decrease rightward along each period of the table, from the alkali metals to the noble gases; and increase down each group. 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 can be explained by the electron shell theory of the atom; they provided important evidence for the development and confirmation of quantum theory.

Atomic radius

Note: All measurements given are in picometers. For more recent data on covalent radii see Covalent radius.
atomic numbersymbolnameempirical [|†]Calculatedvan der WaalsCovalent Covalent Metallic
1Hhydrogen255312038no data
2Hehelium1203114032no data
3Lilithium145167182134no data152
4Beberyllium105112153 a9085112
5Bboron8587192 a8273
6Ccarbon70671707760
7Nnitrogen65561557554
8Ooxygen60481527353
9Ffluorine50421477153
10Neneon1603815469no data
11Nasodium180190227154no data186
12Mgmagnesium150145173130127160
13Alaluminium125118184 a118111143
14Sisilicon110111210111102
15Pphosphorus1009818010694
16Ssulfur1008818010295
17Clchlorine100791759993
18Arargon71711889796
19Kpotassium220243275196no data227
20Cacalcium180194231 a174133197
21Scscandium160184211 a144114162 b
22Tititanium140176no data136108147
23Vvanadium135171no data125106134 b
24Crchromium140166no data127103128 b
25Mnmanganese140161no data139103127 b
26Feiron140156no data125102126 b
27Cocobalt135152no data12696125 b
28Ninickel135149163121101124 b
29Cucopper135145140138120128 b
30Znzinc135142139131no data134 b
31Gagallium130136187126121135 c
32Gegermanium125125211 a122114
33Asarsenic115114185119106
34Seselenium115103190116107
35Brbromine11594185114110
36Krkryptonno data88202110108
37Rbrubidium235265303 a211no data248
38Srstrontium200219249 a192139215
39Yyttrium180212no data162124180 b
40Zrzirconium155206no data148121160
41Nbniobium145198no data137116146 b
42Momolybdenum145190no data145113139 b
43Tctechnetium135183no data156110136 b
44Ruruthenium130178no data126103134 b
45Rhrhodium135173no data135106134 b
46Pdpalladium140169163131112137 b
47Agsilver160165172153137144 b
48Cdcadmium155161158148no data151 b
49Inindium155156193144146167
50Sntin145145217141132
51Sbantimony145133206 a138127
52Tetellurium140123206135121
53Iiodine140115198133125
54Xexenonno data108216130122
55Cscaesium265298343 a225no data265
56Babarium215253268 a198149222
57Lalanthanum195195no data169139187 b
58Cecerium185185no datano data131181.8 c
59Prpraseodymium1852471011128182.4 c
60Ndneodymium1852062020no data181.4 c
61Pmpromethium185205no datano datano data183.4 c
62Smsamarium185238no datano datano data180.4 c
63Eueuropium185231no datano datano data180.4 c
64Gdgadolinium180233no datano data132180.4 c
65Tbterbium175225no datano datano data177.3 c
66Dydysprosium175228no datano datano data178.1 c
67Hoholmium175226no datano datano data176.2 c
68Ererbium175226no datano datano data176.1 c
69Tmthulium175222no datano datano data175.9 c
70Ybytterbium175222no datano datano data176 c
71Lulutetium175217no data160131173.8 c
72Hfhafnium155208no data150122159
73Tatantalum145200no data138119146 b
74Wtungsten135193no data146115139 b
75Rerhenium135188no data159110137 b
76Ososmium130185no data128109135 b
77Iriridium135180no data137107135.5 b
78Ptplatinum135177175128110138.5 b
79Augold135174166144123144 b
80Hgmercury150171155149no data151 b
81Tlthallium190156196148150170
82Pblead180154202147137
83Bibismuth160143207 a146135
84Popolonium190135197 ano data129
85Atastatineno data127202 ano data138
86Rnradonno data120220 a145133
87Frfranciumno datano data348 ano datano datano data
88Raradium215no data283 ano data159no data
89Acactinium195no datano datano data140
90Ththorium180no datano datano data136179 b
91Paprotactinium180no datano datano data129163 d
92Uuranium175no data186no data118156 e
93Npneptunium175no datano datano data116155 e
94Puplutonium175no datano datano datano data159 e
95Amamericium175no datano datano datano data173 b
96Cmcurium176no datano datano datano data174 b
97Bkberkeliumno datano datano datano datano data170 b
98Cfcaliforniumno datano datano datano datano data186+/- 2 b
99Eseinsteiniumno datano datano datano datano data186+/- 2 b
100Fmfermiumno datano datano datano datano datano data
101Mdmendeleviumno datano datano datano datano datano data
102Nonobeliumno datano datano datano datano datano data
103Lrlawrenciumno datano datano datano datano datano data
104Rfrutherfordiumno datano datano datano data131no data
105Dbdubniumno datano datano datano data126no data
106Sgseaborgiumno datano datano datano data121no data
107Bhbohriumno datano datano datano data119no data
108Hshassiumno datano datano datano data118no data
109Mtmeitneriumno datano datano datano data113no data
110Dsdarmstadtiumno datano datano datano data112no data
111Rgroentgeniumno datano datano datano data118no data
112Cncoperniciumno datano datano datano data130no data
113Nhnihoniumno datano datano datano datano datano data
114Flfleroviumno datano datano datano datano datano data
115Mcmoscoviumno datano datano datano datano datano data
116Lvlivermoriumno datano datano datano datano datano data
117Tstennessineno datano datano datano datano datano data
118Ogoganessonno datano datano datano datano datano data

Atomic radius (empirical)

Atomic radius (calculated)

Van der Waals radius

Covalent radii (single bond)

More recent data can be found in Covalent radius. The above values are based on

Triple-bond covalent radii