Exact Masses and Isotopic Abundances of Elements
Based on the Carbon 12 Standard
Name Symbol Mass Abund. Symbol Mass Abund. Symbol Mass Abund.
---------- ------- ---------- ------ ------- ---------- ------ ------- ---------- ------
Aluminum Al(27) 26.981541 100.00
Antimony Sb(121) 120.903824 57.30 Sb(123) 122.904222 42.70
Argon Ar(36) 35.967546 0.34 Ar(38) 37.962732 0.063 Ar(40) 39.962383 99.60
Arsenic As(75) 74.921596 100.00
Barium Ba(130) 129.906277 0.11 Ba(132) 131.905042 0.10 Ba(134) 133.904490 2.42
Ba(135) 134.905668 6.59 Ba(136) 135.904556 7.85 Ba(137) 136.905816 11.23
Ba(138) 137.905236 71.70
Beryllium Be(9) 9.012183 100.00
Bismuth Bi(209) 208.980388 100.00
Boron B(10) 10.012938 19.80 B(11) 11.009305 80.20
Bromine Br(79) 78.918336 50.69 Br(81) 80.916290 49.31
Cadmium Cd(106) 105.906461 1.25 Cd(110) 109.903007 12.49 Cd(111) 110.904182 12.80
Cd(112) 111.902761 24.13 Cd(113) 112.904401 12.22 Cd(114) 113.903361 28.73
Cd(116) 115.904758 7.49
Calcium Ca(40) 39.962591 96.95 Ca(42) 41.958622 0.65 Ca(43) 42.958770 0.14
Ca(44) 43.955485 2.086 Ca(46) 45.953689 0.004 Ca(48) 47.952532 0.19
Carbon C(12) 12.000000 98.90 C(13) 13.003355 1.10
Cerium Ce(136) 135.907140 0.19 Ce(138) 137.905996 0.25 Ce(140) 139.905442 88.48
Ce(142) 141.909249 11.08
Cesium Cs(133) 132.905433 100.00
Chlorine Cl(35) 34.968853 75.77 Cl(37) 36.965903 24.23
Chromium Cr(50) 49.946046 4.35 Cr(52) 51.940510 83.79 Cr(53) 52.940651 9.50
Cr(54) 53.938882 2.36
Cobalt Co(59) 58.933198 100.00
Copper Cu(63) 62.929599 69.17 Cu(65) 64.927792 30.83
Dysprosium Dy(156) 155.924287 0.060 Dy(158) 157.924412 0.10 Dy(160) 159.925203 2.34
Dy(161) 160.926939 18.90 Dy(162) 161.926805 25.50 Dy(163) 162.928737 24.90
Dy(164) 163.929183 28.20
Erbium Er(162) 161.928787 0.14 Er(164) 163.929211 1.61 Er(166) 165.930305 33.60
Er(167) 166.932061 22.95 Er(168) 167.932383 26.80 Er(170) 169.935476 14.90
Europium Eu(151) 150.919860 47.80 Eu(153) 152.921243 52.20
Fluorine F(19) 18.998403 100.00
Gallium Ga(69) 68.925581 60.10 Ga(71) 70.924701 39.90
Gadolinium Gd(152) 151.919803 0.200 Gd(154) 153.920876 2.18 Gd(155) 154.822629 14.80
Gd(156) 155.922130 20.47 Gd(157) 156.923967 15.65 Gd(158) 157.924111 24.84
Gd(160) 159.927061 21.86
Germanium Ge(70) 69.924250 20.50 Ge(72) 71.922080 27.40 Ge(73) 72.923464 7.80
Ge(74) 73.921179 36.50 Ge(76) 75.921403 7.80
Gold Au(197) 196.966560 100.00
Hafnium Hf(174) 173.940065 0.16 Hf(176) 175.941420 5.20 Hf(177) 176.943233 18.60
Hf(178) 177.943710 27.10 Hf(179) 178.945827 13.74 Hf(180) 179.946561 35.20
Helium He(3) 3.016029 .0001 He(4) 4.002603 100.00
Holmium Ho(165) 164.930332 100.00
Hydrogen H(1) 1.007825 99.99 H(2) 2.014102 0.015
Indium In(113) 112.904056 4.30 In(115) 114.903875 95.70
Iodine I(127) 126.904477 100.00
Iridium Ir(191) 190.960603 37.30 Ir(193) 192.962942 62.70
Iron Fe(54) 53.939612 5.80 Fe(56) 55.934939 91.72 Fe(57) 56.935396 2.20
Fe(58) 57.933278 0.28
Krypton Kr(78) 77.920397 0.35 Kr(80) 79.916375 2.25 Kr(82) 81.913483 11.60
Kr(83) 82.914134 11.50 Kr(84) 83.911506 57.00 Kr(86) 85.910614 17.30
Lanthanum La(138) 137.907114 0.09 La(139) 138.906355 99.91
Lead Pb(204) 203.973037 1.40 Pb(206) 205.974455 24.10 Pb(207) 206.975885 22.10
Pb(208) 207.976641 52.40
Lithium Li(6) 6.015123 7.42 Li(7) 7.016005 92.58
Lutetium Lu(175) 174.940785 97.40 Lu(176) 175.942694 2.60
Magnesium Mg(24) 23.985045 78.90 Mg(25) 24.985839 10.00 Mg(26) 25.982595 11.10
Manganese Mn(55) 54.938046 100.00
Mercury Hg(196) 195.965812 0.15 Hg(198) 197.966760 10.10 Hg(199) 198.968269 17.00
Hg(200) 199.968316 23.10 Hg(201) 200.970293 13.20 Hg(202) 201.970632 29.65
Hg(204) 203.973481 6.80
Molybdenum Mo(92) 91.906809 14.84 Mo(94) 93.905086 9.25 Mo(95) 94.905838 15.92
Mo(96) 95.904676 16.68 Mo(97) 96.906018 9.55 Mo(98) 97.905405 24.13
Mo(100) 99.907473 9.63
Neodymium Nd(142) 141.907731 27.13 Nd(143) 142.909823 12.18 Nd(144) 143.910096 23.80
Nd(145) 144.912582 8.30 Nd(146) 145.913126 17.19 Nd(148) 147.916901 5.76
Nd(150) 149.920900 5.64
Neon Ne(20) 19.992439 90.60 Ne(21) 20.993845 0.26 Ne(22) 21.991384 9.20
Nickel Ni(58) 57.935347 68.27 Ni(60) 59.930789 26.10 Ni(61) 60.931059 1.13
Ni(62) 61.928346 3.59 Ni(64) 63.927968 0.91
Niobium Nb(93) 92.906378 100.00
Nitrogen N(14) 14.003074 99.63 N(15) 15.000109 0.37
Osmium Os(184) 183.952514 0.02 Os(186) 185.953852 1.58 Os(187) 186.955762 1.60
Os(188) 187.955850 13.30 Os(189) 188.958156 16.10 Os(190) 189.958455 26.40
Os(192) 191.961487 41.00
Oxygen O(16) 15.994915 99.76 O(17) 16.999131 0.038 O(18) 17.999159 0.20
Palladium Pd(102) 101.905609 1.02 Pd(104) 103.904026 11.14 Pd(105) 104.905075 22.33
Pd(106) 105.903475 27.33 Pd(108) 107.903894 26.46 Pd(110) 109.905169 11.72
Phosphorus P(31) 30.973763 100.00
Platinum Pt(190) 189.959937 0.010 Pt(192) 191.961049 0.79 Pt(194) 193.962679 32.90
Pt(195) 194.964785 33.80 Pt(196) 195.964947 25.30 Pt(198) 197.967879 7.20
Potassium K(39) 38.963708 93.20 K(40) 39.963999 0.012 K(41) 40.961825 6.73
Praseodymium Pr(141) 140.907657 100.00
Rhenium Re(185) 184.952977 37.40 Re(187) 186.955765 62.60
Rhodium Rh(103) 102.905503 100.00
Rubidium Rb(85) 84.911800 72.17 Rb(87) 86.909184 27.84
Ruthenium Ru(96) 95.907596 5.52 Ru(98) 97.905287 1.88 Ru(99) 98.905937 12.70
Ru(100) 99.904218 12.60 Ru(101) 100.905581 17.00 Ru(102) 101.904348 31.60
Ru(104) 103.905422 18.70
Samarium Sm(144) 143.912009 3.10 Sm(147) 146.914907 15.00 Sm(148) 147.914832 11.30
Sm(149) 148.917193 13.80 Sm(150) 149.917285 7.40 Sm(152) 151.919741 25.70
Sm(154) 153.922218 22.70
Scandium Sc(45) 44.955914 100.00
Selenium Se(74) 73.922477 0.90 Se(76) 75.919207 9.00 Se(77) 76.919908 7.60
Se(78) 77.917304 23.50 Se(80) 79.916521 49.60 Se(82) 81.916709 9.40
Silicon Si(28) 27.976928 92.23 Si(29) 28.976496 4.67 Si(30) 29.973772 3.10
Silver Ag(107) 106.905095 51.84 Ag(109) 108.904754 48.16
Sodium Na(23) 22.989770 100.00
Strontium Sr(84) 83.913428 0.56 Sr(86) 85.909273 9.86 Sr(87) 86.908902 7.00
Sr(88) 87.905625 82.58
Sulfur S(32) 31.972072 95.02 S(33) 32.971459 0.75 S(34) 33.967868 4.21
S(36) 35.967079 0.020
Tantalum Ta(180) 179.947489 0.012 Ta(181) 180.948014 99.99
Tellurium Te(122) 121.903055 2.60 Te(123) 122.904278 0.91 Te(124) 123.902825 4.82
Te(125) 124.904435 7.14 Te(126) 125.903310 18.95 Te(128) 127.904464 31.69
Te(130) 129.906229 33.80
Terbium Tb(159) 158.925350 100.00
Thallium Tl(203) 202.972336 29.52 Tl(205) 204.974410 70.48
Thorium Th(232) 232.038054 100.00
Thulium Tm(169) 168.934225 100.00
Tin Sn(116) 115.901744 14.70 Sn(117) 116.902954 7.70 Sn(118) 117.901607 24.30
Sn(119) 118.903310 8.60 Sn(120) 119.902199 32.40 Sn(122) 121.903440 4.60
Sn(124) 123.905271 5.60
Titanium Ti(46) 45.952633 8.00 Ti(47) 46.951765 7.30 Ti(48) 47.947947 73.80
Ti(49) 48.947871 5.50 Ti(50) 49.944786 5.40
Tungsten W(180) 179.946727 0.13 W(182) 181.948225 26.30 W(183) 182.950245 14.30
W(184) 183.950953 30.67 W(186) 185.954377 23.60
Uranium U(234) 234.040947 0.006 U(235) 235.043925 0.72 U(238) 238.050786 99.27
Vanadium V(50) 49.947161 0.25 V(51) 50.943963 99.75
Xenon Xe(128) 127.903531 1.91 Xe(129) 128.904780 26.40 Xe(130) 129.903510 4.10
Xe(131) 130.905076 21.20 Xe(132) 131.904148 26.90 Xe(134) 133.905395 10.40
Xe(136) 135.907219 8.90
Ytterbium Yb(168) 167.933908 0.13 Yb(170) 169.934774 3.05 Yb(171) 170.936338 14.30
Yb(172) 171.936393 21.90 Yb(173) 172.938222 16.12 Yb(174) 173.938873 31.80
Yb(176) 175.942576 12.70
Yttrium Y(89) 88.905856 100.00
Zinc Zn(64) 63.929145 48.60 Zn(66) 65.926035 27.90 Zn(67) 66.927129 4.10
Zn(68) 67.924846 18.80 Zn(70) 69.925325 0.60
Zirconium Zr(90) 89.904708 51.45 Zr(91) 90.905644 11.27 Zr(92) 91.905039 17.17
Zr(94) 93.906319 17.33 Zr(96) 95.908272 2.78
The above data was collected from a compillation from the CRC Handbook and other references.
From http://www.sisweb.com/referenc/source/exactmaa.htm