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.
comments. If you purchase insurance, you may need to understand what a cross liability clause is and what it means. Here are the basics of cross liability clauses and how they work. Cross Liability Clause. If you buy an insurance policy that covers more than one individual, there is always the chance that cross liability could occur.