자연계에 존재하는 인듐은 2종으로 113In과 115In이 있다. 안정 동위 원소인 113In은 자연계에서 4.29%, 방사성 동위 원소인 115In은 95.71%로 방사성 동위 원소가 월등히 많다. 하지만 115In의 반감기는 4.41 x 1014 년으로 우주 나이의 3만배를 초과하기 때문에 사실상 안정 동위 원소처럼 취급해도 무방하다. 인공적으로 합성된 인듐의 동위 원소는 97In부터 135In까지이며 이들 중 111In은 의학적 응용에 이용되는데 뇌조, 뇌실, 뇌종양 등의 촬영하여 장기의 상태를 이미지 진단을 하는데 쓰여진다. 핵자수 Z(p) N(n) 동위 원소 질량 (u) 반감기 붕괴방식IT 이성질핵 전이 붕괴 생성동위 원소 핵스핀 자연계에 존재하는동위 원소범위(몰 분율) 자연계에 존재하는최대 범위(몰 분율) 들뜬 에너지 97In 49 48 96.94954(64)# 5# ms 9/2+# 98In 49 49 97.94214(21)# 45(23) ms32(+32-11) ms β+ 98Cd 0+# 98mIn 0(500)# keV 1.7(8) s1.2(+12-4) s 99In 49 50 98.93422(43)# 3.1(8) s3.0(+8-7) s β+ 99Cd 9/2+# 99mIn 400(150)# keV 1# s 1/2-# 100In 49 51 99.93111(27) 5.9(2) s β+ (96.1%) 100Cd (6,7)+ β+, p (3.9%) 99Ag 101In 49 52 100.92634(32)# 15.1(3) s β+ 100Cd 9/2+# β+, p 100Ag 101mIn 550(100)# keV 10# s 1/2-# 102In 49 53 101.92409(12) 23.3(1) s β+ (99.99%) 102Cd (6+) β+, p (0.00929%) 101Ag 103In 49 54 102.919914(27) 60(1) s β+ 103Cd 9/2+# 103mIn 631.7(1) keV 34(2) s (1/2-)# 104In 49 55 103.91830(9) 1.80(3) min β+ 104Cd 5,6(+) 104mIn 93.48(10) keV 15.7(5) s IT (80%) 104In (3+) β+ (20%) 104Cd 105In 49 56 104.914674(19) 5.07(7) min β+ 105Cd 9/2+ 105mIn 674.1(3) keV 48(6) s IT 105In (1/2)- 106In 49 57 105.913465(13) 6.2(1) min β+ 106Cd 7+ 106mIn 28.6(3) keV 5.2(1) min β+ 106Cd (3+) 107In 49 58 106.910295(12) 32.4(3) min β+ 107Cd 9/2+ 107mIn 678.5(3) keV 50.4(6) s IT 107In 1/2- 108In 49 59 107.909698(10) 58.0(12) min β+ 108Cd 7+ 108mIn 29.75(5) keV 39.6(7) min β+ 108Cd 2+ 109In 49 60 108.907151(6) 4.2(1) h β+ 109Cd 9/2+ 109m1In 650.1(3) keV 1.34(7) min IT 109In 1/2- 109m2In 2101.8(2) keV 209(6) ms (19/2+) 110In 49 61 109.907165(13) 4.9(1) h β+ 110Cd 7+ 110mIn 62.1(5) keV 69.1(5) min β+ 110Cd 2+ 111In 49 62 110.905103(5) 2.8047(5) d ε 111Cd 9/2+ 111mIn 536.95(6) keV 7.7(2) min IT 111In 1/2- 112In 49 63 111.905532(6) 14.97(10) min β+ (56%) 112Cd 1+ β- (44%) 112Sn 112m1In 156.59(5) keV 20.56(6) min β+ 112Cd 4+ 112m2In 350.76(9) keV 690(50) ns 7+ 112m3In 613.69(14) keV 2.81(3) µs 8- 113In 49 64 112.904058(3) 안정 9/2+ 0.0429(5) 113mIn 391.699(3) keV 1.6579(4) h IT 113In 1/2- 114In 49 65 113.904914(3) 71.9(1) s β+ (99.5%) 114Cd 1+ β- (0.5%) 114Sn 114m1In 190.29(3) keV 49.51(1) d IT (96.75%) 114In 5+ β+ (3.25%) 114Cd 114m2In 501.94(3) keV 43.1(6) ms IT (96.75%) 114In (8-) β+ (3.25%) 114Cd 114m3In 641.72(3) keV 4.3(4) µs (7+) 115In 49 66 114.903878(5) 4.41(25)×1014 a β- 115Sn 9/2+ 0.9571(5) 115mIn 336.244(17) keV 4.486(4) h IT (95%) 115In 1/2- β- (5%) 115Sn 116In 49 67 115.905260(5) 14.10(3) s β- 116Sn 1+ ε 116Cd 116m1In 127.267(6) keV 54.29(17) min 5+ 116m2In 289.660(6) keV 2.18(4) s 8- 117In 49 68 116.904514(6) 43.2(3) min β- 117Sn 9/2+ 117mIn 315.302(12) keV 116.2(3) min β- (52.91%) 117Sn 1/2- IT (47.09%) 117In 118In 49 69 117.906354(9) 5.0(5) s β- 118Sn 1+ 118m1In 100(50)# keV 4.364(7) min β- 118Sn 5+ 118m2In 240(50)# keV 8.5(3) s 8- 119In 49 70 118.905845(8) 2.4(1) min β- 119Sn 9/2+ 119m1In 311.37(3) keV 18.0(3) min β- (94.4%) 119Sn 1/2- IT (5.6%) 119In 119m2In 654.27(7) keV 130(15) ns 1/2+,3/2+ 120In 49 71 119.90796(4) 3.08(8) s β- 120Sn 1+ 120m1In 50(60)# keV 46.2(8) s 5+ 120m2In 300(200)# keV 47.3(5) s β- 120Sn 8(-) 121In 49 72 120.907846(29) 23.1(6) s β- 121Sn 9/2+ 121mIn 312.98(8) keV 3.88(10) min β- (98.8%) 121Sn 1/2- IT (1.2%) 121In 122In 49 73 121.91028(5) 1.5(3) s β- 122Sn 1+ 122m1In 40(60)# keV 10.3(6) s 5+ 122m2In 290(140) keV 10.8(4) s β- 122Sn 8- 123In 49 74 122.910438(26) 6.17(5) s β- 123mSn (9/2)+ 123mIn 327.21(4) keV 47.4(4) s β- 123mSn (1/2)- 124In 49 75 123.91318(5) 3.11(10) s β- 124Sn 3+ 124mIn -20(70) keV 3.7(2) s β- 124Sn (8)(-#) IT 124In 125In 49 76 124.91360(3) 2.36(4) s β- 125mSn 9/2+ 125mIn 360.12(9) keV 12.2(2) s β- 125Sn 1/2(-) 126In 49 77 125.91646(4) 1.53(1) s β- 126Sn 3(+#) 126mIn 100(60) keV 1.64(5) s β- 126Sn 8(-#) 127In 49 78 126.91735(4) 1.09(1) s β- (99.97%) 127mSn 9/2(+) β-, n (0.03%) 126Sn 127mIn 460(70) keV 3.67(4) s β- (99.31%) 127mSn (1/2-) β-, n (0.69%) 126Sn 128In 49 79 127.92017(5) 0.84(6) s β- (99.96%) 128Sn (3)+ β-, n (0.038%) 127Sn 128m1In 247.87(10) keV 10(7) ms (1)- 128m2In 320(60) keV 720(100) ms β- 128Sn (8-) 129In 49 80 128.92170(5) 611(4) ms β- (99.75%) 129Sn 9/2+# β-, n (0.25%) 128Sn 129m1In 380(70) keV 1.23(3) s β- (97.2%) 129Sn (1/2-)# β-, n (2.5%) 128Sn IT (.3%) 129In 129m2In 1688.0(5) keV 8.5(5) µs 17/2- 130In 49 81 129.92497(4) 0.29(2) s β- (98.35%) 130Sn 1(-) β-, n (1.65%) 129Sn 130m1In 50(50) keV 538(5) ms 10-# 130m2In 400(60) keV 0.54(1) s (5+) 131In 49 82 130.92685(3) 0.28(3) s β- (97.8%) 131Sn (9/2+) β-, n (2.19%) 130Sn 131m1In 363(37) keV 0.35(5) s (1/2-) 131m2In 4.10(7) MeV 320(60) ms (19/2+ to 23/2+) 132In 49 83 131.93299(7) 206(4) ms β- (94.8%) 132Sn (7-) β-, n (5.2%) 131Sn 133In 49 84 132.93781(32)# 165(3) ms β-, n (85%) 132Sn (9/2+) β- (15%) 133Sn 133mIn 330(40)# keV 180# ms IT 133In (1/2-) 134In 49 85 133.94415(43)# 140(4) ms β- (79%) 134Sn β-, n (17%) 133Sn β-, 2n (4%) 132Sn 135In 49 86 134.94933(54)# 92(10) ms 9/2+# 동위 원소 분류:원소별 동위 원소 목록