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.
Interlock is the fabric I recommend to people who have never worked with knits before â itâs stable, usually has good stretch and recovery, and is generally the easiest knit to work with. Ponte (pon-tee) or ponte de roma is a type of interlock knit, made with a blend of synthetic fibers. French Terry (not pictured) is another type of double knit, but this is made with two yarns; a smooth yarn on one side and a looped yarn on the other side.