Why are graphite layers able to slide past one another?

The ability of graphite layers to slide past one another is a direct consequence of its unique crystal structure. In graphite, carbon atoms are arranged in fused hexagonal rings that form strong, covalently bonded sheets.1

However, the distance between these individual layers is sufficiently large to prevent localized bonding between them. Instead, the layers are held together only by weak van der Waals forces—the result of attraction between the electrons of one carbon atom and the nuclei of neighboring atoms. Because these interlayer forces are significantly weaker than the covalent bonds within the sheets, the layers can easily slide over each other, which accounts for the material's characteristic softness, lubricity, and ready cleavage.12