The presence of dangling bonds can lead to ferromagnetism in materials that are normally magnetically inactive, such as polymers and hydrogenated graphitic materials. A dangling bond contains/consists of an electron and can thus contribute its own net (para) magnetic moment. This only happens when the dangling bond electron does not pair its spin to that of another electron. Ferromagnetic properties in various carbon nanostructures can be described using dangling bonds and may be used to create metal-free organic spintronics and polymeric ferromagnetic materials (see Applications). Creating dangling bonds with unpaired electrons can, for example, be achieved by cutting or putting large mechanical strain on a polymer. In this process, covalent bonds between carbon atoms are broken. One electron can end up on each of the carbon atoms that originally contributed to the bond, leading to two unpaired dangling bonds.