Antimony (51Sb) occurs naturally as two stable isotopes, 121Sb (57.21%) and 123Sb (42.79%). There are 37 artificial radioactive isotopes known with mass numbers 104 to 142, the lightest two of which (104-105Sb) are beyond the proton drip line. Isotopes that are lighter than the stable isotopes tend to decay by β+, and those that are heavier tend to decay by β−; the intermediate 122Sb is observed to decay in both ways.

The longest-lived radioisotopes of antimony are: the minor fission product 125Sb, with a half-life of 2.758 years; 124Sb, with half-life 60.20 days; and 126Sb, with half-life 12.35 days. All other isotopes have half-lives less than 4 days, most less than an hour. Of the numerous isomers reported, the longest-lived is 120m1Sb with half-life 5.76 days; this nuclide has not been confirmed not to be the ground state.

List of isotopes

NuclideZNIsotopic mass (Da)Discovery yearHalf-lifeDecay modeDaughter isotopeSpin and parityNatural abundance (molefraction)
Excitation energyNormal proportionRange of variation
104Sb5153103.936331(24)470(130)msβ+?104Sn
p (<7%)103Sn
β+, p (<7%)103In
α?100In
105Sb5154104.931277(23)1.12(16)sβ+ (>99.9%)105Sn(5/2+)
p (<0.1%)104Sn
β+, p?104In
106Sb5155105.9286380(80)0.6(2)sβ+106Sn(2+)
106mSb103.5(3)keV226(14)nsIT106Sb(4+)
107Sb5156106.9241506(45)4.0(2)sβ+107Sn5/2+#
108Sb5157107.9222267(59)7.4(3)sβ+108Sn(4+)
109Sb5158108.9181412(57)17.2(5)sβ+109Sn5/2+#
110Sb5159109.9168543(64)23.6(3)sβ+110Sn(3+)
111Sb5160110.9132182(95)75(1)sβ+111Sn(5/2+)
112Sb5161111.912400(19)53.5(6)sβ+112Sn(3+)
112mSb825.9(4)keV536(22)nsIT112Sb(8−)
113Sb5162112.909375(18)6.67(7)minβ+113Sn5/2+
114Sb5163113.909289(21)3.49(3)minβ+114Sn3+
114mSb495.5(7)keV219(12)μsIT114Sb(8−)
115Sb5164114.906598(17)32.1(3)minβ+115Sn5/2+
115mSb2796.26(9)keV159(3)nsIT115Sb(19/2)−
116Sb5165115.9067927(55)15.8(8)minβ+116Sn3+
116m1Sb93.99(5)keV194(4)nsIT116Sb1+
116m2Sb390(40)keV60.3(6)minβ+116Sn8−
117Sb5166116.9048415(91)2.97(2)hβ+117Sn5/2+
117m1Sb3130.76(19)keV355(17)μsIT117Sb(25/2)+
117m2Sb3230.7(2)keV290(5)nsIT117Sb(23/2−)
118Sb5167117.9055322(32)3.6(1)minβ+118Sn1+
118m1Sb50.814(21)keV20.6(6)μsIT118Sb3+
118m2Sb250(6)keV5.01(3)hβ+118Sn8−
119Sb5168118.9039441(75)38.19(22)hEC119Sn5/2+
119m1Sb2553.6(3)keV130(3)nsIT119Sb19/2−
119m2Sb2841.7(4)keV835(81)msIT119Sb25/2+
120Sb5169119.9050803(77)15.89(4)minβ+120Sn1+
120m1Sb0(100)#keV5.76(2)dβ+120Sn8−
120m2Sb78.16(5)keV246(2)nsIT120Sb(3+)
120m3Sb2328(100)#keV400(8)nsIT120Sb13+
121Sb5170120.9038114(27)Stable5/2+0.5721(5)
121mSb2751(17)keV179(6)μsIT121Sb(25/2+)
122Sb5171121.9051693(27)2.7238(2)dβ− (97.59%)122Te2−
β+ (2.41%)122Sn
122m1Sb61.4131(5)keV1.86(8)μsIT122Sb3+
122m2Sb137.4726(8)keV0.53(3)msIT122Sb5+
122m3Sb163.5591(17)keV4.191(3)minIT122Sb8−
123Sb5172122.9042153(15)Stable7/2+0.4279(5)
123m1Sb2237.8(3)keV214(3)nsIT123Sb19/2−
123m2Sb2613.4(4)keV65(1)μsIT123Sb23/2+
124Sb5173123.9059371(15)60.20(3)dβ−124Te3−
124m1Sb10.8627(8)keV93(5)sIT (75%)124Sb5+
β− (25%)124Te
124m2Sb36.8440(14)keV20.2(2)minIT124m1Sb(8)−
124m3Sb40.8038(7)keV3.2(3)μsIT124Sb(3+)
125Sb5174124.9052543(27)2.7576(11)yβ−125Te7/2+
125m1Sb1971.25(20)keV4.1(2)μsIT125Sb15/2−
125m2Sb2112.1(3)keV28.5(5)μsIT125Sb19/2−
125m3Sb2471.0(4)keV277.0(64)nsIT125Sb(23/2)+
126Sb5175125.907253(34)12.35(6)dβ−126Te8−
126m1Sb17.7(3)keV19.15(8)minβ− (86%)126Te5+
IT (14%)126Sb
126m2Sb40.4(3)keV~11sIT126m1Sb3−
126m3Sb104.6(3)keV553(5)nsIT126Sb3+
126m4Sb1810.7(17)keV90(16)nsIT126Sb(13+)
127Sb5176126.9069256(55)3.85(5)dβ−127Te7/2+
127m1Sb1920.19(21)keV11.7(1)μsIT127Sb15/2−
127m2Sb2324.7(4)keV269(5)nsIT127Sb23/2+
128Sb5177127.909146(20)9.05(4)hβ−128Te8−
128m1Sb10(6)keV10.41(18)minβ− (96.4%)128Te5+
IT (3.6%)128Sb
128m2Sb1617.3(7)keV500(20)nsIT128Sb(11+)
128m3Sb1769.9(12)keV217(7)nsIT128Sb(13+)
129Sb5178128.909147(23)4.366(26)hβ−129Te7/2+
129m1Sb1851.31(6)keV17.7(1)minβ− (85%)129Te19/2−
IT (15%)129Sb
129m2Sb1861.06(5)keV2.23(17)μsIT129Sb15/2−
129m3Sb2139.4(3)keV0.89(3)μsIT129Sb23/2+
130Sb5179129.911663(15)39.5(8)minβ−130Te8−
130m1Sb4.80(20)keV6.3(2)minβ−130Te4+
130m2Sb84.67(4)keV800(100)nsIT130Sb6−
130m3Sb1508(1)keV600(15)nsIT130Sb(11+)
130m4Sb1544.7(5)keV1.25(1)μsIT130Sb(13+)
131Sb5180130.9119893(22)23.03(4)minβ−131Te7/2+
131m1Sb1676.06(6)keV64.2(26)μsIT131Sb15/2−
131m2Sb1687.2(9)keV4.3(8)μsIT131Sb19/2−
131m3Sb2165.6(15)keV0.97(3)μsIT131Sb23/2+
132Sb5181131.9145141(29)2.79(7)minβ−132Te(4)+
132m1Sb139.3(20)keV4.10(5)minβ−132Te(8−)
132m2Sb254.5(3)keV102(4)nsIT132Sb(6−)
133Sb5182132.9152721(34)2.34(5)minβ−133Te(7/2+)
133mSb4541(9)keV16.54(19)μsIT133Sb(21/2+)
134Sb5183133.9205373(33)674(4)msβ−134Te(0-)
β−, n?133Te
134mSb279(1)keV10.01(4)sβ− (99.91%)134Te(7−)
β−, n (0.088%)133Te
135Sb5184134.9251844(28)1.668(9)sβ− (80.9%)135Te(7/2+)
β−, n (19.1%)134Te
136Sb5185135.9307490(63)0.923(14)sβ− (75.2%)136Te(1−)
β−, n (24.7%)135Te
β−, 2n (0.14%)134Te
136mSb269.3(5)keV570(5)nsIT136Sb(6−)
137Sb5186136.935523(56)497(21)msβ− (51%)137Te7/2+#
β−, n (49%)136Te
β−, 2n?135Te
138Sb5187137.94133(32)#333(7)msβ−, n (72%)137Te(3−)
β− (28%)138Te
β−, 2n?136Te
139Sb5188138.94627(43)#182(9)msβ−, n (90%)138Te7/2+#
β− (10%)139Te
β−, 2n?137Te
140Sb5189139.95235(64)#170(6)msβ− (69%)140Te(3−)
β−, n (23%)139Te
β−, 2n (7.6%)138Te
140mSb330(30)#keV41(8)μsIT140Sb(6−,7−)
141Sb5190140.95755(54)#103(29)msβ−141Te7/2+#
β−, n?140Te
β−, 2n?139Te
142Sb5191141.96392(32)#80(50)msβ−142Te
β−, n?141Te
β−, 2n?140Te
This table header & footer: view

See also

Daughter products other than antimony