Protactinium: bond enthalpies in gaseous diatomic species

The bond energy in the gaseous diatomic species PaPa is (no data) 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 PaX bond enthalpies. All values are quoted in kJ mol-1. Each formula in the table (PaO, PaF, and so on) is a link - select these to see visual periodicity representations for bond enthalpies involving protactinium to elements of your choice.

Period 1

PaH             PaHe

Period 2

PaLi PaBe PaB PaC PaN PaO PaF PaNe
          788.3 ±17.2    

Period 3

PaNa PaMg PaAl PaSi PaP PaS PaCl PaAr

Period 4

PaK PaCa PaGa PaGe PaAs PaSe PaBr PaKr

Period 5

PaRb PaSr PaIn PaSn PaSb PaTe PaI PaXe

Period 6

PaCs PaBa PaTl PaPb PaBi PaPo PaAt PaRn

Period 7

PaFr PaRa            


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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protactinium atomic number