Promethium: bond enthalpies in gaseous diatomic species

The bond energy in the gaseous diatomic species PmPm 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 PmX bond enthalpies. All values are quoted in kJ mol-1. Each formula in the table (PmO, PmF, and so on) is a link - select these to see visual periodicity representations for bond enthalpies involving promethium to elements of your choice.

Period 1

PmH             PmHe

Period 2

PmLi PmBe PmB PmC PmN PmO PmF PmNe
          674 ±63 540 ±42  

Period 3

PmNa PmMg PmAl PmSi PmP PmS PmCl PmAr
          423 ±63    

Period 4

PmK PmCa PmGa PmGe PmAs PmSe PmBr PmKr
          339 ±63    

Period 5

PmRb PmSr PmIn PmSn PmSb PmTe PmI PmXe
          255 ±63    

Period 6

PmCs PmBa PmTl PmPb PmBi PmPo PmAt PmRn

Period 7

PmFr PmRa            


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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promethium atomic number