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.
Cross collateralization is a method used by lenders to add more security to a loan transaction. It is accomplished by the lender placing a lien on another property in addition to the property that is the subject of the loan. Hard money commercial lenders who want to approve a loan request may not feel that the subject property gives them enough security to approve the loan.