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.
clinch. 1  bench clamp - a clamp used to hold work in place on a workbench. 2  C-clamp - a clamp in the shape of the letter C. 3  cramp - a clamp for holding pieces of wood together while they are glued.  holding device - a device for holding 1  something. pipe clamp, pipe vise - a clamp for holding pipe that is to be cut or threaded.