Carbocations are species bearing a formal + charge on carbon. The have sp2 hybridization and trigonal planar geometry, with an empty p orbital on carbon, perpendicular to the plane containing the substituents (see diagrams shown to the right).
Aortic cross-clamp. An aortic cross-clamp is a surgical instrument used in cardiac surgery to clamp the aorta and separate the systemic circulation from the outflow of the heart. An aortic cross-clamping procedure serves, for example, in the repairing of coarctation of the aorta.
Tweezer type of Nipple clamp. Clover clamps. A nipple clamp is a clamp that can be applied to the nipples of any type of body. It is a sex toy which can be attached to the nipples to create pain by restricting blood flow from erect nipples by applying pressure to them. Some people derive erotic pleasure from seeing nipple clamps applied.