How do you measure the bond length for the two atoms?

Answer 1

They are measured by x-ray diffraction, and can also be calculated from several other properties related to the number of electrons in the bond, the dissociation energy and the bond strength. Secondly, most bond lengths are only averages; the atoms forming the bond will vibrate back and forth, stretching and compressing it as the molecule moves and strikes other objects.

Answer 2

Following techniques are used,

• X-Ray diffraction on the crystalline solid which gives the position of atomic centres (not good at resolving position of small atoms)
• Neutron diffraction - allows smaller atoms such as H to be resolved
• Microwave rotational spectra ( gas phase - polar molecules)
• Raman rotational spectroscopy- allows non- polar molecules to be determined

Answer 3

Calculating the bond length of the HCl molecule based on the rotational fine structure of its IR spectrum is a fairly standard p-Chem experiment. Pure rotational (microwave) spectra can also be used.

Answer 4

Bond Order: half the difference between number electrons in bonding molecular orbitals and the number of electrons in anti-bonding molecular orbitals