Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School



Iodine heptafluoride is one of the two1 known compounds of the molecular type AB7, the other being rhenium heptaflouride. Because of this distinction several experimental investigations have attempted to determine the molecular structures, particularly for IF7 . On the basis of infrared and Raman spectra, Lord et al.2 concluded that the IF7 molecule is a pentagonal bipyramid of D5h symmetry. An electronic diffraction study by LaVilla and Bauer3 suggested a similar structure with four of the five equivalent fluorine atoms staggered alternately above and below the median plane. Here the symmetry is reduced to C2. Burbank and Bensey’s4 x-ray crystal structure analysis is consistent with this description, but as Donahue5 illustrates, their data also suggests a displacement of the two apical fluorine atoms from the bipyramidal axis. The resulting structure also has C2 symmetry. (see more in text)

Library of Congress Subject Headings

Molecular rotation
Group theory




South Dakota State University