Oxygen trigonal bipyramid

A model for the intermediate consisting of substrates 36 and 8a coordinated to catalyst 37a was proposed as shown in Scheme 6.30 [74]. In the model 39 the two triflate ligands are dissociated from copper. The ligands are arranged around copper as a trigonal bipyramid and it should be noted that in this model the oxygen atom of the vinyl ether 8a also coordinates to the metal center. However, another tetrahedral intermediate consisting of only the catalyst and the nitrone could also account for the absolute selectivity of the reaction. 

Stable noble gas compounds are restricted to those of xenon. Most of these compounds involve bonds between xenon and the most electronegative elements, fluorine and oxygen. More exotic compounds containing Xe—S, Xe—H, and Xe—C bonds can be formed under carefully controlled conditions, for example in solid matrices at liquid nitrogen temperature. The three Lewis structures below are examples of these compounds in which the xenon atom has a steric munber of 5 and trigonal bipyramidal electron group geometry. 

Diffusion of solutions containing zinc chloride and crown ethers can give solid state structure where the zinc ion is coordinated to the crown ether oxygens.718 A five-coordinate zinc is observed with distorted trigonal-bipyramidal geometry bound to a chloride, a water molecule,... 

Infinite chains of Ag atoms linked by bridging Me2SO units. Coordination about Ag is distorted trigonal bipyramidal with coordination to perchlorate oxygen... 

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