Isotopes of argon
List of isotopes
Bold for stable isotopes Isotopic composition refers to that in air. ³⁶Ar is actually far more abundant than ⁴⁰Ar, universally.

Isotopes of argon

Section Title: List of isotopes
Table Section Text: Bold for stable isotopes Isotopic composition refers to that in air. ³⁶Ar is actually far more abundant than ⁴⁰Ar, universally.

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)	daughter isotope(s)	nuclear spin and parity	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)

excitation energy

30Ar	18	12	30.02156(32)#	<20 ns	p	29Cl	0+

31Ar	18	13	31.01212(22)#	14.4(6) ms	β+, p (55.0%)	30S	5/2(+#)

β+ (40.4%)	31Cl

β+, 2p (2.48%)	29P

β+, 3p (2.1%)	28Si

32Ar	18	14	31.9976380(19)	98(2) ms	β+ (56.99%)	32Cl	0+

β+, p (43.01%)	31S

32mAr	5600(100) keV	unknown	5−#

33Ar	18	15	32.9899257(5)	173.0(20) ms	β+ (61.35%)	33Cl	1/2+

β+, p (38.65%)	32S

34Ar	18	16	33.9802712(4)	844.5(34) ms	β+	34Cl	0+

35Ar	18	17	34.9752576(8)	1.775(4) s	β+	35Cl	3/2+

36Ar	18	18	35.967545106(29)	Observationally Stable	0+	0.003336(4)

37Ar	18	19	36.96677632(22)	35.04(4) d	ε	37Cl	3/2+

38Ar	18	20	37.9627324(4)	Stable	0+	0.000629(1)

39Ar	18	21	38.964313(5)	269(3) y	β−	39K	7/2−	Trace

40Ar	18	22	39.9623831225(29)	Stable	0+	0.996035(4)

41Ar	18	23	40.9645006(4)	109.61(4) min	β−	41K	7/2−

42Ar	18	24	41.963046(6)	32.9(11) y	β−	42K	0+	Trace

43Ar	18	25	42.965636(6)	5.37(6) min	β−	43K	(5/2−)

44Ar	18	26	43.9649240(17)	11.87(5) min	β−	44K	0+

45Ar	18	27	44.9680400(6)	21.48(15) s	β−	45K	(1/2,3/2,5/2)−

46Ar	18	28	45.96809(4)	8.4(6) s	β−	46K	0+

47Ar	18	29	46.97219(11)	1.23(3) s	β− (99%)	47K	3/2−#

β−, n (1%)	46K

48Ar	18	30	47.97454(32)#	0.48(40) s	β−	48K	0+

49Ar	18	31	48.98052(54)#	170(50) ms	β−	49K	3/2−#

50Ar	18	32	49.98443(75)#	85(30) ms	β−	50K	0+

51Ar	18	33	50.99163(75)#	60# ms [>200 ns]	β−	51K	3/2−#

52Ar	18	34	51.99678(97)#	10# ms	β−	52K	0+

53Ar	18	35	53.00494(107)#	3# ms	β−	53K	(5/2−)#

β−, n	52K

Sentence(s)

The isotopes are ³⁹Ar with a half-life of 269 years, ⁴²Ar with a half-life of 32.9 years, and ³⁷Ar with a half-life of 35.04 days.

final_sentence: The isotopes are ³⁹Ar with a half-life of 269 years, ⁴²Ar with a half-life of 32.9 years, and ³⁷Ar with a half-life of 35.04 days.