鏷的同位素均具有放射性，其中最穩定的為 231Pa，質量數在 231 以下的同位素主要發生 α 衰變生成錒，而質量數超過 231 的主要發生 β 衰變生成鈾。 圖表 212Pa styletextalignright 91 styletextalignright 121 21202320 8 8 5 ms 51 6119 ms 7 213Pa styletextalignright 91 styletextalignright 122 21302111 8 7 3 ms 53 4016 ms 209Ac 92 214Pa styletextalignright 91 styletextalignright 123 21402092 8 17 3 ms 210Ac 215Pa styletextalignright 91 styletextalignright 124 21501919 9 14 2 ms 211Ac 92 rowspan2216Pa rowspan2 rowspan2 styletextalignright 91 rowspan2 styletextalignright 125 rowspan221601911 8 rowspan2105 12 ms 80 212Ac rowspan2 rowspan2 20 216Th 217Pa styletextalignright 91 styletextalignright 126 21701832 6 348 9 ms 213Ac 92 rowspan2 styletextindent1em 217mPa rowspan2 rowspan2 colspan3 styletextindent2em 1860 7 keV rowspan2108 3 ms 213Ac rowspan2292 rowspan2 IT （不常見） 217Pa 218Pa styletextalignright 91 styletextalignright 127 218020042 26 0113 1 ms 214Ac rowspan2219Pa rowspan2 rowspan2 styletextalignright 91 rowspan2 styletextalignright 128 rowspan221901988 6 rowspan253 10 ns 215Ac rowspan292 rowspan2 5109 219Th 220Pa styletextalignright 91 styletextalignright 129 22002188 6 780 160 ns 216Ac 1 221Pa styletextalignright 91 styletextalignright 130 22102188 6 49 8 µs 217Ac 92 222Pa styletextalignright 91 styletextalignright 131 22202374 8 32 3 ms 218Ac rowspan2223Pa rowspan2 rowspan2 styletextalignright 91 rowspan2 styletextalignright 132 rowspan222302396 8 rowspan251 6 ms 219Ac rowspan2 rowspan2 001 223Th rowspan2224Pa rowspan2 rowspan2 styletextalignright 91 rowspan2 styletextalignright 133 rowspan2224025626 17 rowspan2844 19 ms 999 220Ac rowspan25 rowspan2 1 224Th 225Pa styletextalignright 91 styletextalignright 134 22502613 8 17 2 s 221Ac 52 rowspan2226Pa rowspan2 rowspan2 styletextalignright 91 rowspan2 styletextalignright 135 rowspan2226027948 12 rowspan218 2 min 74 222Ac rowspan2 rowspan2 26 226Th rowspan2227Pa rowspan2 rowspan2 styletextalignright 91 rowspan2 styletextalignright 136 rowspan2227028805 8 rowspan2383 3 min 85 223Ac rowspan252 rowspan2 15 227Th rowspan2228Pa rowspan2 rowspan2 styletextalignright 91 rowspan2 styletextalignright 137 rowspan2228031051 5 rowspan222 1 h 9815 228Th rowspan23 rowspan2 185 224Ac rowspan2229Pa rowspan2 rowspan2 styletextalignright 91 rowspan2 styletextalignright 138 rowspan22290320968 30 rowspan2150 5 d 9952 229Th rowspan252 rowspan2 48 225Ac styletextindent1em 229mPa colspan3 styletextindent2em 116 3 keV 420 30 ns 32 rowspan3230Pa rowspan3 rowspan3 styletextalignright 91 rowspan3 styletextalignright 139 rowspan3230034541 4 rowspan3174 5 d 916 230Th rowspan32 rowspan3 84 230U 00319 226Ac rowspan4231Pa rowspan4Protoactinium rowspan4 styletextalignright 91 rowspan4 styletextalignright 140 rowspan42310358840 24 rowspan43276 11104 y 227Ac rowspan432 rowspan410000Intermediate decay product of 235U 134109 207Tl24Ne SF 31010 various CD 1012 208Pb23F rowspan2232Pa rowspan2 rowspan2 styletextalignright 91 rowspan2 styletextalignright 141 rowspan2232038592 8 rowspan2131 2 d 232U rowspan22 rowspan2 003 232Th 233Pa styletextalignright 91 styletextalignright 142 2330402473 23 26975 13 d 233U 32 rowspan2234Pa rowspan2Uranium Z rowspan2 styletextalignright 91 rowspan2 styletextalignright 143 rowspan2234043308 5 rowspan2670 5 h 234U rowspan24 rowspan2TraceIntermediate decay product of 238U SF 31010 various rowspan3 styletextindent1em 234mPa rowspan3Uranium X2Brevium rowspan3 colspan3 styletextindent2em 78 3 keV rowspan3117 3 min 9983 234U rowspan30 rowspan3Trace IT 16 234Pa SF 1010 various 235Pa styletextalignright 91 styletextalignright 144 23504544 5 2444 11 min 235U 32 rowspan2236Pa rowspan2 rowspan2 styletextalignright 91 rowspan2 styletextalignright 145 rowspan223604868 21 rowspan291 1 min 236U rowspan21 rowspan2 SF 6108 various 237Pa styletextalignright 91 styletextalignright 146 23705115 11 87 2 min 237U 12 rowspan2238Pa rowspan2 rowspan2 styletextalignright 91 rowspan2 styletextalignright 147 rowspan223805450 6 rowspan2227 9 min 238U rowspan23 rowspan2 SF 26106 various 239Pa styletextalignright 91 styletextalignright 148 23905726 21 18 5 h 239U 32 參考文獻 Isotope masses from Ame2003 Atomic Mass Evaluation by G Audi AH Wapstra C Thibault J Blachot and O Bersillon in Nuclear Physics A729 2003 Halflife spin and isomer data selected from these sources Editing notes on this articles talk page Audi Bersillon Blachot Wapstra The Nubase2003 evaluation of nuclear and decay properties Nuc Phys A 729 pp 3128 2003 National Nuclear Data Center Brookhaven National Laboratory Information extracted from the NuDat 21 database retrieved Sept 2005 David R Lide ed Norman E Holden in CRC Handbook of Chemistry and Physics 85th Edition online version CRC Press Boca Raton Florida 2005 Section 11 Table of the Isotopes Pa category 鏷