Gravity is a force that acts on physical particles. Gravity does not contain molecules, but it acts upon molecules by pulling them toward molecules with a greater gravitational force.
There are two forces acting on every molecule. One is gravity, and the other is magnetism. Sir Isaac Newton (1642–1727) experimented with gravity and came up with a mathematical formula to express how gravitational force works on objects. He determined that it was gravity that pulled the moon in its orbit around earth and that gravity held the planets in their orbits around the sun.
Are you talking about the molecules that contain atoms. These are the only molecules I know of.
All physical matter in this world is made of elements, compounds and mixtures of these. Atom is the smallest divisible particle of an element that possesses all the characteristics qualities of an element. But atoms are not stable in nature. Atoms combine to form molecules which are stable. Molecules that contain only one type of atoms are molecules of chemical substances defined as elements. Molecules containing atoms of more than type are called compounds.
As gravity is not matter, it does not contain molecules, or even atoms.