Isotopes of radon

"Thoron" redirects here. For the genus of wasps, see Thoron (wasp).

There are 39 known isotopes of radon (₈₆Rn), from ¹⁹³Rn to ²³¹Rn; all are radioactive. The most stable isotope is ²²²Rn with a half-life of 3.8215 days, which decays into ²¹⁸
Po.

Isotopes of radon (₈₆Rn)

Main isotopes[1] Decay abun­dance half-life (t1/2) mode pro­duct 210Rn synth 2.4 h α96% 206Po β+4% 210At 211Rn synth 14.6 h β+72.6% 211At α27.4% 207Po 220Rn trace 55.6 s α 216Po 222Rn trace 3.8215 d α 218Po

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Six isotopes of radon, ^217-222Rn, occur in trace quantities in nature as decay products of, respectively, ²¹⁷At, ²¹⁸At, ²²³Ra, ²²⁴Ra, ²²⁵Ra, and ²²⁶Ra. ²¹⁷Rn and ²²¹Rn are produced in rare branches in the decay chain of trace quantities of ²³⁷Np; ²²²Rn (and also ²¹⁸Rn in a rare branch) is an intermediate step in the decay chain of ²³⁸U; ²¹⁹Rn is an intermediate step in the decay chain of ²³⁵U; and ²²⁰Rn occurs in the decay chain of ²³²Th.

List of isotopes

Nuclide [n 1]	Historic name	Z	N	Isotopic mass (Da)[2] [n 2][n 3]	Half-life[1]	Decay mode[1]	Daughter isotope	Spin and parity[1] [n 4][n 5]	Isotopic abundance
		Excitation energy[n 5]
193Rn		86	107	193.009708(27)	1.15(27) ms	α	189Po	(3/2−)
194Rn		86	108	194.006146(18)	780(160) μs	α	190Po	0+
195Rn		86	109	195.005422(55)	7(3) ms	α	191Po	3/2−
195mRn[n 6]		80(50) keV			6(3) ms	α	191Po	13/2+
196Rn		86	110	196.002120(15)	4.7(11) ms	α	192Po	0+
197Rn		86	111	197.001621(17)	54(6) ms	α	193Po	3/2−
197mRn		199(11) keV			25.6(25) ms	α	193Po	13/2+
198Rn		86	112	197.998679(14)	64.4(16) ms	α	194Po	0+
199Rn		86	113	198.9983254(78)	590(30) ms	α	195Po	3/2−
199mRn		220(11) keV			310(20) ms	α	195Po	13/2+
200Rn		86	114	199.9957053(62)	1.09(16) s	α	196Po	0+
200mRn		2320(20)# keV			28(9) μs	IT	200Rn
201Rn		86	115	200.995591(11)	7.0(4) s	α	197Po	3/2−
201mRn		245(12) keV			3.8(1) s	α	197Po	13/2+
202Rn		86	116	201.993264(19)	9.7(1) s	α (78%)	198Po	0+
						β+ (22%)	202At
202mRn		2310(50)# keV			2.22(7) μs	IT	202Rn	11−#
203Rn		86	117	202.9933612(62)	44.2(16) s	α (66%)	199Po	3/2−
						β+ (34%)	203At
203mRn		362(4) keV			26.9(5) s	α (75%)	199Po	13/2+
						β+ (25%)	203At
204Rn		86	118	203.9914437(80)	1.242(23) min	α (72.4%)	200Po	0+
						β+ (27.6%)	204At
205Rn		86	119	204.9917232(55)	170(4) s	β+ (75.4%)	205At	5/2−
						α (24.6%)	201Po
205mRn		657.1(5) keV			>10 s	IT	205Rn	13/2+#
206Rn		86	120	205.9901954(92)	5.67(17) min	α (62%)	202Po	0+
						β+ (38%)	206At
207Rn		86	121	206.9907302(51)	9.25(17) min	β+ (79%)	207At	5/2−
						α (21%)	203Po
207mRn		899.1(10) keV			184.5(9) μs	IT	207Rn	13/2+
208Rn		86	122	207.989635(11)	24.35(14) min	α (62%)	204Po	0+
						β+ (38%)	208At
208mRn		1828.3(4) keV			487(12) ns	IT	208Rn	8+
209Rn		86	123	208.990401(11)	28.8(10) min	β+ (83%)	209At	5/2−
						α (17%)	205Po
209m1Rn		1174.01(13) keV			13.4(13) μs	IT	209Rn	13/2+
209m2Rn		3636.81(23) keV			3.0(3) μs	IT	209Rn	35/2+
210Rn		86	124	209.9896889(49)	2.4(1) h	α (96%)	206Po	0+
						β+ (4%)	210At
210m1Rn		1710(30) keV			644(40) ns	IT	210Rn	8+
210m2Rn		3857(30) keV			1.06(5) μs	IT	210Rn	17−
210m3Rn		6514(30) keV			1.04(7) μs	IT	210Rn	23+
211Rn		86	125	210.9906008(73)	14.6(2) h	β+ (72.6%)	211At	1/2−
						α (27.4%)	207Po
211m1Rn		1603(14)# keV			596(28) ns	IT	211Rn	17/2−
211m2Rn		8905(20)# keV			201(4) ns	IT	211Rn	63/2−
212Rn		86	126	211.9907039(33)	23.9(12) min	α	208Po	0+
212m1Rn		1639.68(15) keV			118(14) ns	IT	212Rn	6+
212m2Rn		1694.1(3) keV			910(30) ns	IT	212Rn	8+
212m3Rn		6174.2(3) keV			102(4) ns	IT	212Rn	22+
212m4Rn		8579.2(4) keV			154(14) ns	IT	212Rn	30+
213Rn		86	127	212.9938851(36)	19.5(1) ms	α[n 7]	209Po	9/2+#
213m1Rn		1682(10) keV			1.00(21) μs	IT	213Rn	(25/2+)
213m2Rn		2205(10) keV			1.36(7) μs	IT	213Rn	(31/2−)
213m3Rn		5965(14) keV			164(11) ns	IT	213Rn	(55/2+)
214Rn		86	128	213.9953627(99)	259(3) ns	α	210Po	0+
214mRn		4595.4(18) keV			245(30) ns	IT	214Rn	(22+)
215Rn		86	129	214.9987450(65)	2.30(10) μs	α[n 8]	211Po	9/2+
216Rn		86	130	216.0002719(62)	29(4) μs	α	212Po	0+
217Rn		86	131	217.0039276(45)	593(38) μs	α	213Po	9/2+	Trace[n 9]
218Rn		86	132	218.0056011(25)	33.75(15) ms	α	214Po	0+	Trace[n 10]
219Rn	Actinon Actinium emanation	86	133	219.0094787(23)	3.96(1) s	α[n 11]	215Po	5/2+	Trace[n 12]
220Rn	Thoron Thorium emanation	86	134	220.0113924(19)	55.6(1) s	α[n 13]	216Po	0+	Trace[n 14]
221Rn		86	135	221.0155356(61)	25.7(5) min	β− (78%)	221Fr	7/2+	Trace[n 9]
						α (22%)	217Po
222Rn[n 15]	Radon[n 16] Radium emanation Emanation Emanon Niton	86	136	222.0175760(21)	3.8215(2) d	α[n 17]	218Po	0+	Trace[n 10]
223Rn		86	137	223.0218893(84)	24.3(4) min	β−	223Fr	7/2+
						α?[n 18]	219Po
224Rn		86	138	224.024096(11)	107(3) min	β−	224Fr	0+
225Rn		86	139	225.028486(12)	4.66(4) min	β−	225Fr	7/2−
226Rn		86	140	226.030861(11)	7.4(1) min	β−	226Fr	0+
227Rn		86	141	227.035304(15)	20.2(4) s	β−	227Fr	(3/2+)
228Rn		86	142	228.037835(19)	65(2) s	β−	228Fr	0+
229Rn		86	143	229.042257(14)	11.9(13) s	β−	229Fr	(5/2+)
230Rn		86	144	230.04527(22)#	24# s [>300 ns]			0+
231Rn		86	145	231.04997(32)#	2# s [>300 ns]			1/2+#
This table header & footer: view

1. ^mRn – Excited nuclear isomer.
2. ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
3. # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
4. ( ) spin value – Indicates spin with weak assignment arguments.
5. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
6. Order of ground state and isomer is uncertain.
7. Theoretically capable of electron capture to ²¹³At; the branching ratio is expected to be <5.8×10⁻⁴% (partial half-life >56.0 min)^[3]
8. Theoretically capable of electron capture to ²¹⁵At; the branching ratio is expected to be <1.0×10⁻¹¹% (partial half-life >266 d)^[4]
9. Intermediate decay product of ²³⁷Np
10. Intermediate decay product of ²³⁸U
11. Theoretically capable of β⁻ decay to ²¹⁹Fr
12. Intermediate decay product of ²³⁵U
13. Theoretically capable of β⁻β⁻ decay to ²²⁰Ra
14. Intermediate decay product of ²³²Th
15. Most common isotope
16. Source of element's name
17. Theoretically capable of β⁻β⁻ decay to ²²²Ra and perhaps β⁻ decay to ²²²Fr^[5]
18. Theoretically capable of α decay with a partial half-life of ~3.65×10⁸ seconds (~11.6 years; branching ratio ~4×10⁻⁴%).^[6][7]