Question

Does BeF2 exist in ortho and para forms?

Hints : (a) Determine the geometry of BeF2, then (b) decide whether fluorine nucei are fermions or bosons.

Answer 1

Yes. BeF2 can exist in ortho and parallel forms.

(a) BeF2 is linear in structure.Flourines occur in two isomeric forms in BeF2, one with its two proton nuclear spins aligned parallel, the other with its two proton spins aligned antiparallel. These two forms are often referred to as spin isomers. Paraflourine is in a lower energy state than is orthoflourine.

(b) A proton is a half-integer particle and so is an electron. Therefore, the net spin of a normal flourine atom is one, which is an integer. Therefore, flourine is a composite boson.