Isotopes of radium

Radium (88Ra) has no stable or nearly stable isotopes, and thus a standard atomic weight cannot be given. The longest lived, and most common, isotope of radium is 226Ra with a half-life of $1,600 years$. 226Ra occurs in the decay chain of 238U (often referred to as the radium series). Radium has 34 known isotopes from 201Ra to 234Ra.

In 2013 it was discovered that the nucleus of radium-224 is pear-shaped. This was the first discovery of an asymmetrical nucleus.

List of isotopes

 * 201Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 113
 * α
 * 197Rn
 * (3/2−)
 * style="text-indent:1em" | 201mRa
 * colspan="3" style="text-indent:2em" | 260(30) keV
 * α
 * 197mRn
 * (13/2+)
 * 202Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 114
 * 202.00989(7)
 * α
 * 198Rn
 * 0+
 * rowspan=2|203Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 115
 * rowspan=2|203.00927(9)
 * rowspan=2|4(3) ms
 * α
 * 199Rn
 * rowspan=2|(3/2−)
 * rowspan=2|
 * β+ (rare)
 * 203Fr
 * rowspan=2 style="text-indent:1em" | 203mRa
 * rowspan=2|
 * rowspan=2 colspan="3" style="text-indent:2em" | 220(90) keV
 * rowspan=2|41(17) ms
 * α
 * 199Rn
 * rowspan=2|(13/2+)
 * rowspan=2|
 * β+ (rare)
 * 203Fr
 * rowspan=2|204Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 116
 * rowspan=2|204.006500(17)
 * rowspan=2|60(11) ms [59(+12−9) ms]
 * α (99.7%)
 * 200Rn
 * rowspan=2|0+
 * rowspan=2|
 * β+ (.3%)
 * 204Fr
 * rowspan=2|205Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 117
 * rowspan=2|205.00627(9)
 * rowspan=2|220(40) ms [210(+60−40) ms]
 * α
 * 201Rn
 * rowspan=2|(3/2−)
 * rowspan=2|
 * β+ (rare)
 * 205Fr
 * rowspan=2 style="text-indent:1em" | 205mRa
 * rowspan=2|
 * rowspan=2 colspan="3" style="text-indent:2em" | 310(110)# keV
 * rowspan=2|180(50) ms [170(+60−40) ms]
 * α
 * 201Rn
 * rowspan=2|(13/2+)
 * rowspan=2|
 * IT (rare)
 * 205Ra
 * 206Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 118
 * 206.003827(19)
 * 0.24(2) s
 * α
 * 202Rn
 * 0+
 * rowspan=2|207Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 119
 * rowspan=2|207.00380(6)
 * rowspan=2|1.3(2) s
 * α (90%)
 * 203Rn
 * rowspan=2|(5/2−, 3/2−)
 * rowspan=2|
 * β+ (10%)
 * 207Fr
 * rowspan=3 style="text-indent:1em" | 207mRa
 * rowspan=3|
 * rowspan=3 colspan="3" style="text-indent:2em" | 560(50) keV
 * rowspan=3|57(8) ms
 * IT (85%)
 * 207Ra
 * rowspan=3|(13/2+)
 * rowspan=3|
 * α (15%)
 * 203Rn
 * β+ (.55%)
 * 207Fr
 * rowspan=2|208Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 120
 * rowspan=2|208.001840(17)
 * rowspan=2|1.3(2) s
 * α (95%)
 * 204Rn
 * rowspan=2|0+
 * rowspan=2|
 * β+ (5%)
 * 208Fr
 * style="text-indent:1em" | 208mRa
 * colspan="3" style="text-indent:2em" | 1800(200) keV
 * 270 ns
 * (8+)
 * rowspan=2|209Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 121
 * rowspan=2|209.00199(5)
 * rowspan=2|4.6(2) s
 * α (90%)
 * 205Rn
 * rowspan=2|5/2−
 * rowspan=2|
 * β+ (10%)
 * 209Fr
 * rowspan=2|210Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 122
 * rowspan=2|210.000495(16)
 * rowspan=2|3.7(2) s
 * α (96%)
 * 206Rn
 * rowspan=2|0+
 * rowspan=2|
 * β+ (4%)
 * 210Fr
 * style="text-indent:1em" | 210mRa
 * colspan="3" style="text-indent:2em" | 1800(200) keV
 * 2.24 μs
 * (8+)
 * rowspan=2|211Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 123
 * rowspan=2|211.000898(28)
 * rowspan=2|13(2) s
 * α (97%)
 * 207Rn
 * rowspan=2|5/2(−)
 * rowspan=2|
 * β+ (3%)
 * 211Fr
 * rowspan=2|212Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 124
 * rowspan=2|211.999794(12)
 * rowspan=2|13.0(2) s
 * α (85%)
 * 208Rn
 * rowspan=2|0+
 * rowspan=2|
 * β+ (15%)
 * 212Fr
 * style="text-indent:1em" | 212m1Ra
 * colspan="3" style="text-indent:2em" | 1958.4(5) keV
 * 10.9(4) μs
 * (8)+
 * style="text-indent:1em" | 212m2Ra
 * colspan="3" style="text-indent:2em" | 2613.4(5) keV
 * 0.85(13) μs
 * (11)−
 * rowspan=2|213Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 125
 * rowspan=2|213.000384(22)
 * rowspan=2|2.74(6) min
 * α (80%)
 * 209Rn
 * rowspan=2|1/2−
 * rowspan=2|
 * β+ (20%)
 * 213Fr
 * rowspan=2 style="text-indent:1em" | 213mRa
 * rowspan=2|
 * rowspan=2 colspan="3" style="text-indent:2em" | 1769(6) keV
 * rowspan=2|2.1(1) ms
 * IT (99%)
 * 213Ra
 * rowspan=2|17/2−#
 * rowspan=2|
 * α (1%)
 * 209Rn
 * rowspan=2|214Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 126
 * rowspan=2|214.000108(10)
 * rowspan=2|2.46(3) s
 * α (99.94%)
 * 210Rn
 * rowspan=2|0+
 * rowspan=2|
 * β+ (.06%)
 * 214Fr
 * 215Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 127
 * 215.002720(8)
 * 1.55(7) ms
 * α
 * 211Rn
 * (9/2+)#
 * style="text-indent:1em" | 215m1Ra
 * colspan="3" style="text-indent:2em" | 1877.8(5) keV
 * 7.1(2) μs
 * (25/2+)
 * style="text-indent:1em" | 215m2Ra
 * colspan="3" style="text-indent:2em" | 2246.9(5) keV
 * 1.39(7) μs
 * (29/2−)
 * style="text-indent:1em" | 215m3Ra
 * colspan="3" style="text-indent:2em" | 3756.6(6)+X keV
 * 0.555(10) μs
 * (43/2−)
 * rowspan=2|216Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 128
 * rowspan=2|216.003533(9)
 * rowspan=2|182(10) ns
 * α
 * 212Rn
 * rowspan=2|0+
 * rowspan=2|
 * EC (<1×10−8%)
 * 216Fr
 * 217Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 129
 * 217.006320(9)
 * 1.63(17) μs
 * α
 * 213Rn
 * (9/2+)
 * 218Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 130
 * 218.007140(12)
 * 25.2(3) μs
 * α
 * 214Rn
 * 0+
 * 219Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 131
 * 219.010085(9)
 * 10(3) ms
 * α
 * 215Rn
 * (7/2)+
 * 220Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 132
 * 220.011028(10)
 * 17.9(14) ms
 * α
 * 216Rn
 * 0+
 * rowspan=2|221Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 133
 * rowspan=2|221.013917(5)
 * rowspan=2|28(2) s
 * α
 * 217Rn
 * rowspan=2|5/2+
 * rowspan=2|Trace
 * CD (1.2×10−10%)
 * 207Pb 14C
 * rowspan=2|222Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 134
 * rowspan=2|222.015375(5)
 * rowspan=2|38.0(5) s
 * α
 * 218Rn
 * rowspan=2|0+
 * rowspan=2|
 * CD (3×10−8%)
 * 208Pb 14C
 * rowspan=2|223Ra
 * rowspan=2|Actinium X
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 135
 * rowspan=2|223.0185022(27)
 * rowspan=2|11.43(5) d
 * α
 * 219Rn
 * rowspan=2|3/2+
 * rowspan=2|Trace
 * CD (6.4×10−8%)
 * 209Pb 14C
 * rowspan=2|224Ra
 * rowspan=2|Thorium X
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 136
 * rowspan=2|224.0202118(24)
 * rowspan=2|3.6319(23) d
 * α
 * 220Rn
 * rowspan=2|0+
 * rowspan=2|Trace
 * CD (4.3×10−9%)
 * 210Pb 14C
 * rowspan=2| 225Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 137
 * rowspan=2| 225.023612(3)
 * rowspan=2| 14.9(2) d
 * β−
 * 225Ac
 * rowspan=2| 1/2+
 * rowspan=2| Trace
 * α (2.0%)
 * 221Rn
 * rowspan=2|226Ra
 * rowspan=2|Radium
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 138
 * rowspan=2|226.0254098(25)
 * rowspan=2|1600(7) y
 * α
 * 222Rn
 * rowspan=2|0+
 * rowspan=2|Trace
 * CD (2.6×10−9%)
 * 212Pb 14C
 * 227Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 139
 * 227.0291778(25)
 * 42.2(5) min
 * β−
 * 227Ac
 * 3/2+
 * 228Ra
 * Mesothorium 1
 * style="text-align:right" | 88
 * style="text-align:right" | 140
 * 228.0310703(26)
 * 5.75(3) y
 * β−
 * 228Ac
 * 0+
 * Trace
 * 229Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 141
 * 229.034958(20)
 * 4.0(2) min
 * β−
 * 229Ac
 * 5/2(+)
 * 230Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 142
 * 230.037056(13)
 * 93(2) min
 * β−
 * 230Ac
 * 0+
 * 231Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 143
 * 231.04122(32)#
 * 103(3) s
 * β−
 * 231Ac
 * (5/2+)
 * style="text-indent:1em" | 231mRa
 * colspan="3" style="text-indent:2em" | 66.21(9) keV
 * ~53 μs
 * (1/2+)
 * 232Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 144
 * 232.04364(30)#
 * 250(50) s
 * β−
 * 232Ac
 * 0+
 * 233Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 145
 * 233.04806(50)#
 * 30(5) s
 * β−
 * 233Ac
 * 1/2+#
 * 234Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 146
 * 234.05070(53)#
 * 30(10) s
 * β−
 * 234Ac
 * 0+
 * rowspan=2|224Ra
 * rowspan=2|Thorium X
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 136
 * rowspan=2|224.0202118(24)
 * rowspan=2|3.6319(23) d
 * α
 * 220Rn
 * rowspan=2|0+
 * rowspan=2|Trace
 * CD (4.3×10−9%)
 * 210Pb 14C
 * rowspan=2| 225Ra
 * rowspan=2|
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 137
 * rowspan=2| 225.023612(3)
 * rowspan=2| 14.9(2) d
 * β−
 * 225Ac
 * rowspan=2| 1/2+
 * rowspan=2| Trace
 * α (2.0%)
 * 221Rn
 * rowspan=2|226Ra
 * rowspan=2|Radium
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2 style="text-align:right" | 138
 * rowspan=2|226.0254098(25)
 * rowspan=2|1600(7) y
 * α
 * 222Rn
 * rowspan=2|0+
 * rowspan=2|Trace
 * CD (2.6×10−9%)
 * 212Pb 14C
 * 227Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 139
 * 227.0291778(25)
 * 42.2(5) min
 * β−
 * 227Ac
 * 3/2+
 * 228Ra
 * Mesothorium 1
 * style="text-align:right" | 88
 * style="text-align:right" | 140
 * 228.0310703(26)
 * 5.75(3) y
 * β−
 * 228Ac
 * 0+
 * Trace
 * 229Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 141
 * 229.034958(20)
 * 4.0(2) min
 * β−
 * 229Ac
 * 5/2(+)
 * 230Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 142
 * 230.037056(13)
 * 93(2) min
 * β−
 * 230Ac
 * 0+
 * 231Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 143
 * 231.04122(32)#
 * 103(3) s
 * β−
 * 231Ac
 * (5/2+)
 * style="text-indent:1em" | 231mRa
 * colspan="3" style="text-indent:2em" | 66.21(9) keV
 * ~53 μs
 * (1/2+)
 * 232Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 144
 * 232.04364(30)#
 * 250(50) s
 * β−
 * 232Ac
 * 0+
 * 233Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 145
 * 233.04806(50)#
 * 30(5) s
 * β−
 * 233Ac
 * 1/2+#
 * 234Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 146
 * 234.05070(53)#
 * 30(10) s
 * β−
 * 234Ac
 * 0+
 * 232Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 144
 * 232.04364(30)#
 * 250(50) s
 * β−
 * 232Ac
 * 0+
 * 233Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 145
 * 233.04806(50)#
 * 30(5) s
 * β−
 * 233Ac
 * 1/2+#
 * 234Ra
 * style="text-align:right" | 88
 * style="text-align:right" | 146
 * 234.05070(53)#
 * 30(10) s
 * β−
 * 234Ac
 * 0+
 * style="text-align:right" | 88
 * style="text-align:right" | 146
 * 234.05070(53)#
 * 30(10) s
 * β−
 * 234Ac
 * 0+