Calcium: bond enthalpies in gaseous diatomic species

The bond energy in the gaseous diatomic species CaCa is <= 46 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 CaX bond enthalpies. All values are quoted in kJ mol-1. Each formula in the table (CaO, CaF, and so on) is a link - select these to see visual periodicity representations for bond enthalpies involving calcium to elements of your choice.

Period 1

CaH             CaHe

Period 2

CaLi CaBe CaB CaC CaN CaO CaF CaNe
84.9 ±8.4         402.1 ±16.7 527 ±21  

Period 3

CaNa CaMg CaAl CaSi CaP CaS CaCl CaAr
          337.6 ±18.8 409 ±9  

Period 4

CaK CaCa CaGa CaGe CaAs CaSe CaBr CaKr
  <= 46         310.9 ±9.2  

Period 5

CaRb CaSr CaIn CaSn CaSb CaTe CaI CaXe
            284.7 ±8.4  

Period 6

CaCs CaBa CaTl CaPb CaBi CaPo CaAt CaRn

Period 7

CaFr CaRa            


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.

WebElements Shop

WebElements now has a WebElements shop at which you can buy periodic table posters, mugs, T-shirts, games, fridge magnets, molecular models, and more.

Periodic Table fridge magnets Periodic Table fridge magnets
Buy our periodic table fridge magnets here

WebElements poster Periodic table t-shirts Periodic table mouse mats Molymod molecular model kits Chemistry educational resources

calcium atomic number