Astatine: bond enthalpies in gaseous diatomic species

The bond energy in the gaseous diatomic species AtAt is about 80 kJ mol-1.

The following values refer to neutral heterodiatomic molecules in the gas phase. These numbers may well differ considerably from, say, single bond energies in a solid. All values are given in kJ mol-1.

Table of diatomic AtX bond enthalpies. All values are quoted in kJ mol-1. Each formula in the table (AtO, AtF, and so on) is a link - select these to see visual periodicity representations for bond enthalpies involving astatine to elements of your choice.

Period 1

AtH             AtHe

Period 2

AtLi AtBe AtB AtC AtN AtO AtF AtNe

Period 3

AtNa AtMg AtAl AtSi AtP AtS AtCl AtAr

Period 4

AtK AtCa AtGa AtGe AtAs AtSe AtBr AtKr

Period 5

AtRb AtSr AtIn AtSn AtSb AtTe AtI AtXe

Period 6

AtCs AtBa AtTl AtPb AtBi AtPo AtAt AtRn

Period 7

AtFr AtRa            


I am grateful to Professor J.A. Kerr (University of Birmingham, UK) for the provision of the bond strengths of diatomic molecules data.

The values given here are at 298 K. All values are quoted in kJ mol-1. Generally, these data were obtained by spectroscopic or mass spectrometric means. You should consult reference 1 for further details. A note of caution: the strength of, say, the C-H bond in the gaseous diatomic species CH (not an isolable species) is not necessarily, the same as the strength of a C-H bond in, say, methane.

The strongest bond for a diatomic species is that of carbon monoxide, CO (1076.5 ± 0.4 kJ mol-1). The strongest bond for a homonuclear diatomic species is that of dinitrogen, N2 (945.33 ± 0.59 kJ mol-1).


  1. J.A. Kerr in CRC Handbook of Chemistry and Physics 1999-2000 : A Ready-Reference Book of Chemical and Physical Data (CRC Handbook of Chemistry and Physics, D.R. Lide, (ed.), CRC Press, Boca Raton, Florida, USA, 81st edition, 2000.

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astatine atomic number