Природното појавување на европиумот (63Eu) е составен од два изотопи, 151Eu и 153Eu, со 153Eu кои се најзастапени (52,2% природна застапеност). Додека 153Eu е набљудувачки стабилен (теоретски може да претрпи алфа распаѓање со полураспад над 5,5×1017 години), било откриено дека 151Eu во 2007 година е нестабилен и подложен на алфа распаѓање. Полураспадот се мери на (4.62 ± 0,95 (стат.) ± 0,68 (сист.)) × 1018 години што одговара на еден алфа-распад на две минути во секој килограм природен европиум. Покрај природниот радиоизотоп 151Eu, се карактеризираат и 36 вештачки радиоизотопи, од кои најстабилни се 150Еu со полураспад од 36,9 години, 152Eu со полураспад од 13,516 години, 154Eu со полураспад од 8,593 години и 155Eu со полураспад од 4.7612 години. Поголемиот дел од преостанатите радиоактивни изотопи, кои се движат од 130Eu до 170Eu, имаат полураспад што е помал од 12,2 секунди. Овој елемент има и 18 метастабилни изомери, од кои најстабилни се 150mEu (t1/2 12,8 часа), 152m1Eu (t1/2 9,3116 часа) и 152 m5Eu (t1/2 96 минути).
Примарниот режим на распаѓање пред најзастапениот стабилен изотоп, 153Eu, е електронски зафат, а примарниот режим после е бета-распад. Примарните распадни производи пред 153Eu се изотопи на самариумот, а примарните производи потоа се изотопи на гадолиниумот.
Список на изотопи
|-id=Europium-130 | 130Eu | style="text-align:right" | 63 | style="text-align:right" | 67 | 129.96402(58)# | 1.0(4) ms | p | 129Sm | (1+)
|-id=Europium-131 | rowspan=3|131Eu | rowspan=3 style="text-align:right" | 63 | rowspan=3 style="text-align:right" | 68 | rowspan=3|130.95763(43)# | rowspan=3|17.8(19) ms | p (89%) | 130Sm | rowspan=3|3/2+ | rowspan=3| | rowspan=3| |- | β+ (?%) | 131Sm |- | β+, p (?%) | 130Pm |-id=Europium-134 | rowspan=2|134Eu | rowspan=2 style="text-align:right" | 63 | rowspan=2 style="text-align:right" | 71 | rowspan=2|133.94654(32)# | rowspan=2|0.5(2) s | β+ | 134Sm | rowspan=2| | rowspan=2| | rowspan=2| |- | β+, p (?%) | 133Pm |-id=Europium-135 | 135Eu | style="text-align:right" | 63 | style="text-align:right" | 72 | 134.94187(21)# | 1.5(2) s | β+ | 135Sm | 5/2+#
|-id=Europium-136 | rowspan=2|136Eu | rowspan=2 style="text-align:right" | 63 | rowspan=2 style="text-align:right" | 73 | rowspan=2|135.93962(21)# | rowspan=2|3.3(3) s | β+ (99.91%) | 136Sm | rowspan=2|6+# | rowspan=2| | rowspan=2| |- | β+, p (0.09%) | 135Pm |-id=Europium-136m | rowspan=2 style="text-indent:1em" | 136mEuРедоследот на основната состојба и изомерот е непознат. | rowspan=2 colspan="3" style="text-indent:2em" | 100(100)# keV | rowspan=2|3.8(3) s | β+ (99.91%) | 136Sm | rowspan=2|1+# | rowspan=2| | rowspan=2| |- | β+, p (0.09%) | 135Pm |-id=Europium-137 | 137Eu | style="text-align:right" | 63 | style="text-align:right" | 74 | 136.9354307(47) | 8.4(5) s | β+ | 137Sm | 5/2+#
|-id=Europium-138 | 138Eu | style="text-align:right" | 63 | style="text-align:right" | 75 | 137.933709(30) | 5# s
| 2−#
|-id=Europium-138m | style="text-indent:1em" | 138mEu | colspan="3" style="text-indent:2em" | 100(50)# keV | 12.1(6) s | β+ | 138Sm | 7−#
|-id=Europium-139 | 139Eu | style="text-align:right" | 63 | style="text-align:right" | 76 | 138.929792(14) | 17.9(6) s | β+ | 139Sm | (11/2)−
|-id=Europium-139m | style="text-indent:1em" | 139mEu | colspan="3" style="text-indent:2em" | 148.3(3) keV | 10(2) μs | ИП | 139Eu | (7/2+)
|-id=Europium-140 | rowspan=2|140Eu | rowspan=2 style="text-align:right" | 63 | rowspan=2 style="text-align:right" | 77 | rowspan=2|139.928088(55) | rowspan=2|1.51(2) s | β+ (95.1%) | rowspan=2|140Sm | rowspan=2|1+ | rowspan=2| | rowspan=2| |- | ЕЗ (4.9%) |-id=Europium-140m1 | rowspan=2 style="text-indent:1em" | 140m1Eu | rowspan=2 colspan="3" style="text-indent:2em" | 210(14) keV | rowspan=2|125(2) ms | ИП (>99%) | 140Eu | rowspan=2|(5−) | rowspan=2| | rowspan=2| |- | β+ (>1%) | 140Sm |-id=Europium-140m2 | style="text-indent:1em" | 140m2Eu | colspan="3" style="text-indent:2em" | 669(14) keV | 299.8(21) ns | ИП | 140Eu | (8+)
|-id=Europium-141 | 141Eu | style="text-align:right" | 63 | style="text-align:right" | 78 | 140.924932(14) | 40.7(7) s | β+ | 141Sm | 5/2+
|-id=Europium-141m | rowspan=2 style="text-indent:1em" | 141mEu | rowspan=2 colspan="3" style="text-indent:2em" | 96.45(7) keV | rowspan=2|2.7(3) s | ИП (86%) | 141Eu | rowspan=2|11/2− | rowspan=2| | rowspan=2| |- | β+ (14%) | 141Sm |-id=Europium-142 | rowspan=2|142Eu | rowspan=2 style="text-align:right" | 63 | rowspan=2 style="text-align:right" | 79 | rowspan=2|141.923447(32) | rowspan=2|2.36(10) s | β+ (89.9%) | 142Sm | rowspan=2|1+ | rowspan=2| | rowspan=2| |- | ЕЗ (11.1%) | 142Sm |-id=Europium-142m | style="text-indent:1em" | 142mEu | colspan="3" style="text-indent:2em" | 450(30) keV | 1.223(8) min | β+ | 142Sm | 8−
|-id=Europium-143 | 143Eu | style="text-align:right" | 63 | style="text-align:right" | 80 | 142.920299(12) | 2.59(2) min | β+ | 143Sm | 5/2+
|-id=Europium-143m | style="text-indent:1em" | 143mEu | colspan="3" style="text-indent:2em" | 389.51(4) keV | 50.0(5) μs | ИП | 143Eu | 11/2−
|-id=Europium-144 | 144Eu | style="text-align:right" | 63 | style="text-align:right" | 81 | 143.918819(12) | 10.2(1) s | β+ | 144Sm | 1+
|-id=Europium-144m | style="text-indent:1em" | 144mEu | colspan="3" style="text-indent:2em" | 1127.6(6) keV | 1.0(1) μs | ИП |144Eu | 8−
|-id=Europium-145 | 145Eu | style="text-align:right" | 63 | style="text-align:right" | 82 | 144.9162727(33) | 5.93(4) d | β+ | 145Sm | 5/2+
|-id=Europium-145m | style="text-indent:1em" | 145mEu | colspan="3" style="text-indent:2em" | 716.0(3) keV | 490(30) ns | ИП | 145Eu | 11/2−
|-id=Europium-146 | 146Eu | style="text-align:right" | 63 | style="text-align:right" | 83 | 145.9172109(65) | 4.61(3) d | β+ | 146Sm | 4−
|-id=Europium-146m | style="text-indent:1em" | 146mEu | colspan="3" style="text-indent:2em" | 666.33(11) keV | 235(3) μs | ИП | 146Eu | 9+
|-id=Europium-147 | rowspan=2|147Eu | rowspan=2 style="text-align:right" | 63 | rowspan=2 style="text-align:right" | 84 | rowspan=2|146.9167524(28) | rowspan=2|24.1(6) d | β+ | 147Sm | rowspan=2|5/2+ | rowspan=2| | rowspan=2| |- | α (0.0022%) | 143Pm |-id=Europium-147m | style="text-indent:1em" | 147mEu | colspan="3" style="text-indent:2em" | 625.27(5) keV | 765(15) ns | ИП | 147Eu | 11/2−
|-id=Europium-148 | rowspan=2|148Eu | rowspan=2 style="text-align:right" | 63 | rowspan=2 style="text-align:right" | 85 | rowspan=2|147.918091(11) | rowspan=2|54.5(5) d | β+ | 148Sm | rowspan=2|5− | rowspan=2| | rowspan=2| |- | α (9.4×10−7%) | 144Pm |-id=Europium-148m | style="text-indent:1em" | 148mEu | colspan="3" style="text-indent:2em" | 720.4(3) keV | 162(8) ns | ИП | 148Eu | 9+
|-id=Europium-149 | 149Eu | style="text-align:right" | 63 | style="text-align:right" | 86 | 148.9179369(42) | 93.1(4) d | EC | 149Sm | 5/2+
|-id=Europium-149m | style="text-indent:1em" | 149mEu | colspan="3" style="text-indent:2em" | 496.386(2) keV | 2.45(5) μs | ИП | 149Eu | 11/2−
|-id=Europium-150 | 150Eu | style="text-align:right" | 63 | style="text-align:right" | 87 | 149.9197071(67) | 36.9(9) y | β+ | 150Sm | 5−
|-id=Europium-150m | rowspan=3 style="text-indent:1em" | 150mEu | rowspan=3 colspan="3" style="text-indent:2em" | 41.7(10) keV | rowspan=3|12.8(1) h | β− (89%) | 150Gd | rowspan=3|0− | rowspan=3| | rowspan=3| |- | β+ (11%) | 150Sm |- | ИП (<5×10−8%) | 150Eu |-id=Europium-151 | 151EuПрвобитен радионуклид | style="text-align:right" | 63 | style="text-align:right" | 88 | 150.9198566(13) | 4.6(12)×1018 y | α | 147Pm | 5/2+ | 0.4781(6) | |-id=Europium-151m | style="text-indent:1em" | 151mEu | colspan="3" style="text-indent:2em" | 196.245(10) keV | 58.9(5) μs | ИП | 151Eu | 11/2−
|-id=Europium-152 | rowspan=2|152Eu | rowspan=2 style="text-align:right" | 63 | rowspan=2 style="text-align:right" | 89 | rowspan=2|151.9217510(13) | rowspan=2|13.517(6) y | β+ (72.08%) | 152Sm | rowspan=2|3− | rowspan=2| | rowspan=2| |- | β− (27.92%) | 152Gd |-id=Europium-152m1 | rowspan=2 style="text-indent:1em" | 152m1Eu | rowspan=2 colspan="3" style="text-indent:2em" | 45.5998(4) keV | rowspan=2|9.3116(13) h | β− (73%) | 152Gd | rowspan=2|0− | rowspan=2| | rowspan=2| |- | β+ (27%) | 152Sm |-id=Europium-152m2 | style="text-indent:1em" | 152m2Eu | colspan="3" style="text-indent:2em" | 65.2969(4) keV | 940(80) ns | ИП | 152Eu | 1−
|-id=Europium-152m3 | style="text-indent:1em" | 152m3Eu | colspan="3" style="text-indent:2em" | 78.2331(4) keV | 165(10) ns | ИП | 152Eu | 1+
|-id=Europium-152m4 | style="text-indent:1em" | 152m4Eu | colspan="3" style="text-indent:2em" | 89.8496(4) keV | 384(10) ns | ИП | 152Eu | 4+
|-id=Europium-152m5 | style="text-indent:1em" | 152m5Eu | colspan="3" style="text-indent:2em" | 147.86(10) keV | 95.8(4) min | ИП | 152Eu | 8−
|-id=Europium-153 | 153EuПроизводи на цепење | style="text-align:right" | 63 | style="text-align:right" | 90 | 152.9212368(13) | colspan=3 align=center|Набљудувачки стабиленСе верува дека подлежи на α распад на 149Pm со полураспад | 5/2+ | 0.5219(6) | |-id=Europium-153m | style="text-indent:1em" | 153mEu | colspan="3" style="text-indent:2em" | 1771.0(4) keV | 475(10) ns | ИП | 153Eu | 19/2−
|-id=Europium-154 | rowspan=2|154Eu | rowspan=2 style="text-align:right" | 63 | rowspan=2 style="text-align:right" | 91 | rowspan=2|153.9229857(13) | rowspan=2|8.592(3) y | β− (99.98%) | 154Gd | rowspan=2|3− | rowspan=2| | rowspan=2| |- | ЕЗ (0.018%) | 154Sm |-id=Europium-154m1 | style="text-indent:1em" | 154m1Eu | colspan="3" style="text-indent:2em" | 68.1702(4) keV | 2.2(1) μs | ИП | 154Eu | 2+
|-id=Europium-154m2 | style="text-indent:1em" | 154m2Eu | colspan="3" style="text-indent:2em" | 145.3(3) keV | 46.3(4) min | ИП | 154Eu | (8−)
| 155Eu | style="text-align:right" | 63 | style="text-align:right" | 92 | 154.9228998(13) | 4.742(8) y | β− | 155Gd | 5/2+
|-id=Europium-156 | 156Eu | style="text-align:right" | 63 | style="text-align:right" | 93 | 155.9247630(38) | 15.19(8) d | β− | 156Gd | 0+
|-id=Europium-157 | 157Eu | style="text-align:right" | 63 | style="text-align:right" | 94 | 156.9254326(45) | 15.18(3) h | β− | 157Gd | 5/2+
|-id=Europium-158 | 158Eu | style="text-align:right" | 63 | style="text-align:right" | 95 | 157.9277822(22) | 45.9(2) min | β− | 158Gd | 1−
|-id=Europium-159 | 159Eu | style="text-align:right" | 63 | style="text-align:right" | 96 | 158.9290995(46) | 18.1(1) min | β− | 159Gd | 5/2+
|-id=Europium-160 | 160Eu | style="text-align:right" | 63 | style="text-align:right" | 97 | 159.93183698(97) | 42.6(5) s | β− | 160Gd | (5−)
|-id=Europium-160m | style="text-indent:1em" | 160mEu | colspan="3" style="text-indent:2em" | 93.0(12) keV | 30.8(5) s | ИП | 160Eu | (1−)
|-id=Europium-161 | 161Eu | style="text-align:right" | 63 | style="text-align:right" | 98 | 160.933664(11) | 26.2(23) s | β− | 161Gd | 5/2+#
|-id=Europium-162 | 162Eu | style="text-align:right" | 63 | style="text-align:right" | 99 | 161.9369583(14) | ~10 s | β− | 162Gd | 1+#
|-id=Europium-162m | style="text-indent:1em" | 162mEu | colspan="3" style="text-indent:2em" | 158.0(17) keV | 15.0(5) s | ИП | 162Eu | (6+)
|-id=Europium-163 | 163Eu | style="text-align:right" | 63 | style="text-align:right" | 100 | 162.93926551(97) | 7.7(4) s | β− | 163Gd | 5/2+#
|-id=Europium-163m | style="text-indent:1em" | 163mEu | colspan="3" style="text-indent:2em" | 964.5(5) keV | 911(24) ns | ИП | 163Eu | (13/2−)
|-id=Europium-164 | 164Eu | style="text-align:right" | 63 | style="text-align:right" | 101 | 163.9428529(22) | 4.16(19) s | β− | 164Gd | 3−#
|-id=Europium-165 | 165Eu | style="text-align:right" | 63 | style="text-align:right" | 102 | 164.9455401(56) | | β− | 165Gd | 5/2+#
|-id=Europium-166 | rowspan=2|166Eu | rowspan=2 style="text-align:right" | 63 | rowspan=2 style="text-align:right" | 103 | rowspan=2|165.94981(11)# | rowspan=2| | β− (99.37%) | 166Gd | rowspan=2|0−# | rowspan=2| | rowspan=2| |- | β−, n (0.63%) | 165Gd |-id=Europium-167 | rowspan=2|167Eu | rowspan=2 style="text-align:right" | 63