This page deals with the electron affinity as a property of isolated atoms or molecules (i.e. in the gas phase). Solid state electron affinities are not listed here.
Electron affinity can be defined in two equivalent ways. First, as the energy that is released by adding an electron to an isolated gaseous atom. The second (reverse) definition is that electron affinity is the energy required to remove an electron from a singly charged gaseous negative ion. The latter can be regarded as the ionization energy of the –1 ion or the zeroth ionization energy.[1] Either convention can be used.
Negative electron affinities can be used in those cases where electron capture requires energy, i.e. when capture can occur only if the impinging electron has a kinetic energy large enough to excite a resonance of the atom-plus-electron system. Conversely electron removal from the anion formed in this way releases energy, which is carried out by the freed electron as kinetic energy. Negative ions formed in these cases are always unstable. They may have lifetimes of the order of microseconds to milliseconds, and invariably autodetach after some time.
| Z | Element | Name | Electron affinity (eV) | Electron affinity (kJ/mol) | References | |||
|---|---|---|---|---|---|---|---|---|
| 1 | 1H | Hydrogen | data-sort-value="0.754195" | 0.754 195(19) | data-sort-value="72.769" | 72.769(2) | ||
| 1 | 2H | Deuterium | data-sort-value="0.75467" | 0.754 67(4) | data-sort-value="72.814" | 72.814(4) | ||
| 2 | He | Helium | data-sort-value="-0.5" | −0.5(2) | data-sort-value="-48" | −48(20) | est. | |
| 3 | Li | Lithium | data-sort-value="0.61804922" | 0.618 049(22) | data-sort-value="59.632" | 59.632 6(21) | ||
| 4 | Be | Beryllium | data-sort-value="-0.5" | −0.5(2) | data-sort-value="-48" | −48(20) | est. | |
| 5 | B | Boron | data-sort-value="0.27972325" | 0.279 723(25) | data-sort-value="26.989" | 26.989(3) | ||
| 6 | 12C | Carbon | data-sort-value="1.262122611" | 1.262 122 6(11) | data-sort-value="121.7763" | 121.776 3(1) | ||
| 6 | 13C | Carbon | data-sort-value="1.2621136" | 1.262 113 6(12) | data-sort-value="121.7755" | 121.775 5(2) | ||
| 7 | N | Nitrogen | data-sort-value="-0.07" | −0.07 | data-sort-value="-6.8" | −6.8 | ||
| 8 | 16O | Oxygen | data-sort-value="1.46111297" | 1.461 112 97(9) | data-sort-value="140.976" | 140.975 970(9) | ||
| 8 | 17O | Oxygen | data-sort-value="1.461108" | 1.461 108(4) | data-sort-value="140.9755" | 140.975 5(3) | ||
| 8 | 18O | Oxygen | data-sort-value="1.461105" | 1.461 105(3) | data-sort-value="140.9752" | 140.975 2(3) | ||
| 9 | F | Fluorine | data-sort-value="3.4011898" | 3.401 189 8(24) | data-sort-value="328.164" | 328.164 9(3) | ||
| 10 | Ne | Neon | data-sort-value="-1.2" | −1.2(2) | data-sort-value="-116" | −116(19) | est. | |
| 11 | Na | Sodium | data-sort-value="0.547926" | 0.547 926(25) | data-sort-value="52.867" | 52.867(3) | ||
| 12 | Mg | Magnesium | data-sort-value="-0.4" | −0.4(2) | data-sort-value="-40" | −40(19) | est. | |
| 13 | Al | Aluminium | data-sort-value="0.43283" | 0.432 83(5) | data-sort-value="41.762" | 41.762(5) | ||
| 14 | Si | Silicon | data-sort-value="1.3895212" | 1.389 521 2(8) | data-sort-value="134.068" | 134.068 4(1) | ||
| 15 | P | Phosphorus | data-sort-value="0.746609" | 0.746 609(11) | data-sort-value="72.037" | 72.037(1) | ||
| 16 | 32S | Sulfur | data-sort-value="2.0771042" | 2.077 104 2(6) | data-sort-value="200.410" | 200.410 1(1) | ||
| 16 | 34S | Sulfur | data-sort-value="2.0771045" | 2.077 104 5(12) | data-sort-value="200.410" | 200.410 1(2) | ||
| 17 | Cl | Chlorine | data-sort-value="3.612725" | 3.612 725(28) | data-sort-value="348.575" | 348.575(3) | ||
| 18 | Ar | Argon | data-sort-value="-1.0" | −1.0(2) | data-sort-value="-96" | −96(20) | est. | |
| 19 | K | Potassium | data-sort-value="0.501459" | 0.501 459(13) | data-sort-value="48.383" | 48.383(2) | ||
| 20 | Ca | Calcium | data-sort-value="0.02455" | 0.024 55(10) | data-sort-value="2.37" | 2.37(1) | ||
| 21 | Sc | Scandium | data-sort-value="0.17938" | 0.179 380(23) | data-sort-value="17.3076" | 17.307 6(22) | ||
| 22 | Ti | Titanium | data-sort-value="0.07554" | 0.075 54(5) | data-sort-value="7.289" | 7.289(5) | ||
| 23 | V | Vanadium | data-sort-value="0.52766" | 0.527 66(20) | data-sort-value="50.911" | 50.911(20) | ||
| 24 | Cr | Chromium | data-sort-value="0.67593" | 0.675 928(27) | data-sort-value="65.2172" | 65.217 2(26) | ||
| 25 | Mn | Manganese | data-sort-value="-0.5" | −0.5(2) | data-sort-value="-50" | −50(19) | est. | |
| 26 | Fe | Iron | data-sort-value="0.153236" | 0.153 236(35) | data-sort-value="14.785" | 14.785(4) | ||
| 27 | Co | Cobalt | data-sort-value="0.662255" | 0.662 255(47) | data-sort-value="63.8979" | 63.897 9(45) | ||
| 28 | Ni | Nickel | data-sort-value="1.15716" | 1.157 16(12) | data-sort-value="111.65" | 111.65(2) | ||
| 29 | Cu | Copper | data-sort-value="1.23578" | 1.235 78(4) | data-sort-value="119.235" | 119.235(4) | ||
| 30 | Zn | Zinc | data-sort-value="-0.6" | −0.6(2) | data-sort-value="-58" | −58(20) | est. | |
| 31 | Ga | Gallium | data-sort-value="0.301166" | 0.301 166(15) | data-sort-value="29.0581" | 29.058 1(15) | ||
| 32 | Ge | Germanium | data-sort-value="1.2326764" | 1.232 676 4(13) | data-sort-value="118.935" | 118.935 2(2) | ||
| 33 | As | Arsenic | data-sort-value="0.8048" | 0.804 8(2) | data-sort-value="77.65" | 77.65(2) | ||
| 34 | Se | Selenium | data-sort-value="2.0206047" | 2.020 604 7(12) | data-sort-value="194.958" | 194.958 7(2) | ||
| 35 | Br | Bromine | data-sort-value="3.363588" | 3.363 588(3) | data-sort-value="324.536" | 324.536 9(3) | ||
| 36 | Kr | Krypton | data-sort-value="-1.0" | −1.0(2) | data-sort-value="-96" | −96(20) | est. | |
| 37 | Rb | Rubidium | data-sort-value="0.485916" | 0.485 916(21) | data-sort-value="46.884" | 46.884(3) | ||
| 38 | Sr | Strontium | data-sort-value="0.05206" | 0.052 06(6) | data-sort-value="5.023" | 5.023(6) | ||
| 39 | Y | Yttrium | data-sort-value="0.31129" | 0.311 29(22) | data-sort-value="30.035" | 30.035(21) | ||
| 40 | Zr | Zirconium | data-sort-value="0.43328" | 0.433 28(9) | data-sort-value="41.806" | 41.806(9) | ||
| 41 | Nb | Niobium | data-sort-value="0.91740" | 0.917 40(7) | data-sort-value="88.516" | 88.516(7) | ||
| 42 | Mo | Molybdenum | data-sort-value="0.74723" | 0.747 23(8) | data-sort-value="72.097" | 72.097(8) | ||
| 43 | Tc | Technetium | data-sort-value="0.55" | 0.55(20) | data-sort-value="53" | 53(20) | est. | |
| 44 | Ru | Ruthenium | data-sort-value="1.04627" | 1.046 27(2) | data-sort-value="100.95" | 100.950(3) | ||
| 45 | Rh | Rhodium | data-sort-value="1.14289" | 1.142 89(20) | data-sort-value="110.27" | 110.27(2) | ||
| 46 | Pd | Palladium | data-sort-value="0.56214" | 0.562 14(12) | data-sort-value="54.24" | 54.24(2) | ||
| 47 | Ag | Silver | data-sort-value="1.30447" | 1.304 47(3) | data-sort-value="125.862" | 125.862(3) | ||
| 48 | Cd | Cadmium | data-sort-value="-0.7" | −0.7(2) | data-sort-value="-68" | −68(20) | est. | |
| 49 | In | Indium | data-sort-value="0.38392" | 0.383 92(6) | data-sort-value="37.043" | 37.043(6) | ||
| 50 | Sn | Tin | data-sort-value="1.112070" | 1.112 070(2) | data-sort-value="107.298" | 107.298 4(3) | ||
| 51 | Sb | Antimony | data-sort-value="1.047401" | 1.047 401(19) | data-sort-value="101.059" | 101.059(2) | ||
| 52 | Te | Tellurium | data-sort-value="1.970875" | 1.970 875(7) | data-sort-value="190.161" | 190.161(1) | ||
| 53 | 127I | Iodine | data-sort-value="3.0590465" | 3.059 046 5(37) | data-sort-value="295.1531" | 295.153 1(4) | ||
| 53 | 128I | Iodine | data-sort-value="3.059052" | 3.059 052(38) | data-sort-value="295.154" | 295.154(4) | ||
| 54 | Xe | Xenon | data-sort-value="-0.8" | −0.8(2) | data-sort-value="-77" | −77(20) | est. | |
| 55 | Cs | Caesium | data-sort-value="0.4715983" | 0.4715983(38) | data-sort-value="45.5023" | 45.5023(4) | [2] | |
| 56 | Ba | Barium | data-sort-value="0.14462" | 0.144 62(6) | data-sort-value="13.954" | 13.954(6) | ||
| 57 | La | Lanthanum | data-sort-value="0.557546" | 0.557 546(20) | data-sort-value="53.795" | 53.795(2) | ||
| 58 | Ce | Cerium | data-sort-value="0.60016" | 0.600 160(27) | data-sort-value="57.9067" | 57.906 7(26) | ||
| 59 | Pr | Praseodymium | data-sort-value="0.10923" | 0.109 23(46) | data-sort-value="10.539" | 10.539(45) | ||
| 60 | Nd | Neodymium | data-sort-value="0.09749" | 0.097 49(33) | data-sort-value="9.406" | 9.406(32) | ||
| 61 | Pm | Promethium | data-sort-value="0.129" | 0.129 | data-sort-value="12.45" | 12.45 | ||
| 62 | Sm | Samarium | data-sort-value="0.162" | 0.162 | data-sort-value="15.63" | 15.63 | ||
| 63 | Eu | Europium | data-sort-value="0.116" | 0.116(13) | data-sort-value="11.2" | 11.2(13) | ||
| 64 | Gd | Gadolinium | data-sort-value="0.212" | 0.212(30) | data-sort-value="20.5" | 20.5(29) | ||
| 65 | Tb | Terbium | data-sort-value="0.13131" | 0.131 31(80) | data-sort-value="12.670" | 12.670(77) | ||
| 66 | Dy | Dysprosium | data-sort-value="0.015" | 0.015(3) | data-sort-value="1.45" | 1.45(30) | ||
| 67 | Ho | Holmium | data-sort-value="0.338" | 0.338 | data-sort-value="32.61" | 32.61 | ||
| 68 | Er | Erbium | data-sort-value="0.312" | 0.312 | data-sort-value="30.10" | 30.10 | ||
| 69 | Tm | Thulium | data-sort-value="1.029" | 1.029(22) | data-sort-value="99" | 99(3) | ||
| 70 | Yb | Ytterbium | data-sort-value="-0.02" | −0.02 | data-sort-value="-1.93" | −1.93 | est. | |
| 71 | Lu | Lutetium | data-sort-value="0.2388" | 0.238 8(7) | data-sort-value="23.04" | 23.04(7) | ||
| 72 | Hf | Hafnium | data-sort-value="0.1780" | 0.178 0(7) | data-sort-value="17.18" | 17.18(7) | < | --Pan . Lin. Beck. Donald R.. 21 December 2009 . Calculations of Hf− electron affinity and photodetachment partial cross sections. Journal of Physics B: Atomic, Molecular and Optical Physics. IOP Publishing Ltd . 43 . 2 . 22 September 2015. |
| 73 | Ta | Tantalum | data-sort-value="0.328859" | 0.328 859(23) | data-sort-value="31.7301" | 31.730 1(22) | ||
| 74 | W | Tungsten | data-sort-value="0.81626" | 0.816 26(8) | data-sort-value="78.76" | 78.76(1) | ||
| 75 | Re | Rhenium | data-sort-value="0.060396" | 0.060 396(64) | data-sort-value="5.8273" | 5.827 3(62) | ||
| 76 | Os | Osmium | data-sort-value="1.077661" | 1.077 661(24) | data-sort-value="103.9785" | 103.978 5(24) | ||
| 77 | Ir | Iridium | data-sort-value="1.564057" | 1.564 057(12) | data-sort-value="150.909" | 150.908 6(12) | ||
| 78 | Pt | Platinum | data-sort-value="2.12510" | 2.125 10(5) | data-sort-value="205.041" | 205.041(5) | ||
| 79 | Au | Gold | data-sort-value="2.308610" | 2.308 610(25) | data-sort-value="222.747" | 222.747(3) | ||
| 80 | Hg | Mercury | data-sort-value="-0.5" | −0.5(2) | data-sort-value="-48" | −48(20) | est. | |
| 81 | Tl | Thallium | data-sort-value="0.320053" | 0.320 053(19) | data-sort-value="30.8804" | 30.880 4(19) | ||
| 82 | Pb | Lead | data-sort-value="0.356721" | 0.356 721(2) | data-sort-value="34.4183" | 34.418 3(3) | ||
| 83 | Bi | Bismuth | data-sort-value="0.942362" | 0.942 362(13) | data-sort-value="90.924" | 90.924(2) | ||
| 84 | Po | Polonium | data-sort-value="1.40" | 1.40(7) | data-sort-value="136" | 136(7) | calc. | |
| 85 | At | Astatine | data-sort-value="2.41578" | 2.415 78(7) | data-sort-value="233.087" | 233.087(8) | ||
| 86 | Rn | Radon | data-sort-value="-0.7" | −0.7(2) | data-sort-value="-68" | −68(20) | est. | |
| 87 | Fr | Francium | data-sort-value="0.486" | 0.486 | data-sort-value="46.89" | 46.89 | est. | |
| 88 | Ra | Radium | data-sort-value="0.10" | 0.10 | data-sort-value="9.6485" | 9.648 5 | est. | |
| 89 | Ac | Actinium | data-sort-value="0.35" | 0.35 | data-sort-value="33.77" | 33.77 | est. | |
| 90 | Th | Thorium | data-sort-value="0.60769" | 0.607 69(6) | data-sort-value="58.633" | 58.633(6) | ||
| 91 | Pa | Protactinium | data-sort-value="0.55" | 0.55 | data-sort-value="53.03" | 53.03 | est. | |
| 92 | U | Uranium | data-sort-value="0.31497" | 0.314 97(9) | data-sort-value="30.39" | 30.390(9) | ||
| 93 | Np | Neptunium | data-sort-value="0.48" | 0.48 | data-sort-value="45.85" | 45.85 | est. | |
| 94 | Pu | Plutonium | data-sort-value="-0.50" | −0.50 | data-sort-value="-48.33" | −48.33 | est. | |
| 95 | Am | Americium | data-sort-value="0.10" | 0.10 | data-sort-value="9.93" | 9.93 | est. | |
| 96 | Cm | Curium | data-sort-value="0.28" | 0.28 | data-sort-value="27.17" | 27.17 | est. | |
| 97 | Bk | Berkelium | data-sort-value="-1.72" | −1.72 | data-sort-value="-165.24" | −165.24 | est. | |
| 98 | Cf | Californium | data-sort-value="-1.01" | −1.01 | data-sort-value="-97.31" | −97.31 | est. | |
| 99 | Es | Einsteinium | data-sort-value="-0.30" | −0.30 | data-sort-value="-28.60" | −28.60 | est. | |
| 100 | Fm | Fermium | data-sort-value="0.35" | 0.35 | data-sort-value="33.96" | 33.96 | est. | |
| 101 | Md | Mendelevium | data-sort-value="0.98" | 0.98 | data-sort-value="93.91" | 93.91 | est. | |
| 102 | No | Nobelium | data-sort-value="-2.33" | −2.33 | data-sort-value="-223.22" | −223.22 | est. | |
| 103 | Lr | Lawrencium | data-sort-value="-0.31" | −0.31 | data-sort-value="-30.04" | −30.04 | est. | |
| 111 | Rg | Roentgenium | data-sort-value="1.565" | 1.565 | data-sort-value="151.0" | 151.0 | calc.[3] | |
| 113 | Nh | Nihonium | data-sort-value="0.69" | 0.69 | data-sort-value="66.6" | 66.6 | calc. | |
| 115 | Mc | Moscovium | data-sort-value="0.366" | 0.366 | data-sort-value="35.3" | 35.3 | calc. | |
| 116 | Lv | Livermorium | data-sort-value="0.776" | 0.776 | data-sort-value="74.9" | 74.9 | calc. | |
| 117 | Ts | Tennessine | data-sort-value="1.719" | 1.719 | data-sort-value="165.9" | 165.9 | calc.[4] | |
| 118 | Og | Oganesson | data-sort-value="0.080" | 0.080(6) | data-sort-value="7.72" | 7.72(58) | calc.[5] | |
| 119 | Uue | Ununennium | data-sort-value="0.662" | 0.662 | data-sort-value="63.87" | 63.87 | calc. | |
| 120 | Ubn | Unbinilium | data-sort-value="0.021" | 0.021 | data-sort-value="2.03" | 2.03 | calc.[6] | |
| 121 | Ubu | Unbiunium | data-sort-value="0.57" | 0.57 | data-sort-value="55" | 55 | calc. |
The electron affinities Eea of some molecules are given in the table below, from the lightest to the heaviest. Many more have been listed by . The electron affinities of the radicals OH and SH are the most precisely known of all molecular electron affinities.
| Molecule | Name | Eea (eV) | Eea (kJ/mol) | References |
|---|---|---|---|---|
| Diatomics | ||||
| 16OH | Hydroxyl | 1.827 6488(11) | 176.3413(2) | |
| 16OD | 1.825 53(4) | 176.137(5) | ||
| C2 | Dicarbon | 3.269(6) | 315.4(6) | |
| BO | Boron oxide | 2.508(8) | 242.0(8) | |
| NO | Nitric oxide | 0.026(5) | 2.5(5) | |
| O2 | Dioxygen | 0.450(2) | 43.42(20) | |
| 32SH | Sulfhydryl | 2.314 7283(17) | 223.3373(2) | |
| F2 | Difluorine | 3.08(10) | 297(10) | |
| Cl2 | Dichlorine | 2.35(8) | 227(8) | |
| Br2 | Dibromine | 2.53(8) | 244(8) | |
| I2 | Diiodine | 2.524(5) | 243.5(5) | |
| IBr | Iodine monobromide | 2.512(3) | 242.4(4) | |
| LiCl | Lithium chloride | 0.593(10) | 57.2(10) | |
| FeO | Iron(II) oxide | 1.4950(5) | 144.25(6) | |
| CN | Cyano radical | 3.862(4) | [7] | |
| Triatomics | ||||
| NO2 | Nitrogen dioxide | 2.273(5) | 219.3(5) | |
| O3 | Ozone | 2.1028(25) | 202.89(25) | |
| SO2 | Sulfur dioxide | 1.107(8) | 106.8(8) | |
| Larger polyatomics | ||||
| CH2CHO | Vinyloxy | 1.8248(+2-6) | 176.07(+3-7) | after |
| C6H6 | Benzene | −0.70(14) | −68(14) | |
| C6H4O2 | p-Benzoquinone | 1.860(5) | 179.5(6) | |
| BF3 | Boron trifluoride | 2.65(10) | 256(10) | |
| HNO3 | Nitric acid | 0.57(15) | 55(14) | |
| CH3NO2 | Nitromethane | 0.172(6) | 16.6(6) | |
| POCl3 | Phosphoryl chloride | 1.41(20) | 136(20) | |
| SF6 | Sulfur hexafluoride | 1.03(5) | 99.4(49) | |
| C2(CN)4 | Tetracyanoethylene | 3.17(20) | 306(20) | |
| WF6 | Tungsten hexafluoride | 3.5(1) | 338(10) | |
| UF6 | Uranium hexafluoride | 5.06(20) | 488(20) | NIST chemistry webbook after |
| C60 | Buckminsterfullerene | 2.6835(6) | 258.92(6) | |
| Z | Element | Name | Electron affinity (eV) | Electron affinity (kJ/mol) | References | ||
|---|---|---|---|---|---|---|---|
| 7 | N− | Nitrogen | data-sort-value="-6.98" | -6.98 | data-sort-value="-0.0000048" | -673 | [8] |
| 7 | N2− | Nitrogen | data-sort-value="-11.09" | -11.09 | data-sort-value="-0.0000076" | -1070 | |
| 8 | O− | Oxygen | data-sort-value="-7.71" | -7.71 | data-sort-value="-0.0000053" | -744 | |
| 15 | P− | Phosphorus | data-sort-value="-4.85" | -4.85 | data-sort-value="-0.0000033" | -468 | |
| 15 | P2− | Phosphorus | data-sort-value="-9.18" | -9.18 | data-sort-value="-0.0000063" | -886 | |
| 16 | S− | Sulfur | data-sort-value="-4.73" | -4.73 | data-sort-value="-0.0000032" | -456 | |
| 33 | As− | Arsenic | data-sort-value="-4.51" | -4.51 | data-sort-value="-0.0000031" | -435 | |
| 33 | As2− | Arsenic | data-sort-value="-8.31" | -8.31 | data-sort-value="-0.0000057" | -802 | |
| 34 | Se− | Selenium | data-sort-value="-4.25" | -4.25 | data-sort-value="-0.0000029" | -410 | |