According to my handbook, rutile (\(TiO_2\)) has a primitive tetragonal cell consisting of 6 atoms. How is that possible when each lattice point contains 1/8 atom or molecule?

 

Found this on Google - http://web.ukonline.co.uk/aplr/structure.htm

 

How is that possible when each lattice point contains 1/8 atom or molecule?

The rutile structure is not close packed. It shows 6:3 coordination which means that each titanium atom is surrounded by 6 (not 8) oxygen atoms arranged at the vertices of an octahedron.

An octahedon has 8 faces but only 6 vertices

Each oxygen is coordinated to 3 titaniums in a planar equilateral triangle.