Structure of vanadium dioxide

Abstract

GOLDSCHMIDT1 came to the conclusion that vanadium dioxide had a rutile structure in which, in its idealized form, each vanadium would be surrounded by a regular octahedral arrangement of oxygen atoms. In fact, in actual rutile structures, the regular octahedral arrangement must always be lost2 (as is in fact observed), though the unit cell will remain tetragonal, because four of the metal oxygen (or halogen) distances will remain equal. The other two could be different without any loss of symmetry, but it is found that usually they have virtually the same length as the other four (for example, in titanium dioxide four of 1.94 Å. and two of 1.99 Å. and in magnesium fluoride four of 2.00 Å. and two of 1.98 Å.)3. The arrangement of the six cations around a metal atom in a tetragonal rutile structure may therefore be visualized as "one at the north pole, one at the south, and four on the equator as a rectangle". © 1962 Nature Publishing Group.