Pentagonal Nuclei

These compounds differ from the benzene derivatives in containing pentagonal in place of hexagonal nuclei thus  

Furfuran—C H40—is a product of the distillation of lir-wood, and is also formed from dehydrofurfuran, CiHjO, obtained from erythrite. 

It is a colorless, oily liquid, having the odor of chloroform. By acting upon pyrrol with an ethereal solution of iodin, a quadri-substituted derivative, tetriodopyrrol, C4HI4N, is obtained as a brown powder, which has been used under the name iodol as a substitute for iodoform in surgical practice. 

The molecule of pyrrol may be further modified by the introduction of further N atoms to produce  

The constitution and relations of antipyrin are shown by the following formulae  

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Figure 8. Demonstration of the structure of the building block of iO with the capsule (host) and encapsulated Keggin-type cluster nucleus (guest) the metal Mo72Fejo)capsule is shown in wire frame representation -with the 30 Fe " centers (highlighted as spheres) linking the 12 (Mo)Mo5) pentagons - and the Keggin nucleus in polyhedral representation.

The first rule means that two valence electrons on an atom sit diametrically opposite each other on either side of the nucleus three form a triangle around the nucleus four arrange themselves at the corners of a tetrahedron five form either a square pyramid or a trigonal bipyramid six are on the corners of an octahedron seven form a pentagonal bipyramid and eight a square antiprisma, a cube, or two interlaced tetrahedra. 

The southern nucleus of the play a consists of massive salt, and in areas that are frequently flooded (the eastern side) the surface salt has a beautiful clear white-to-pink color, and is uniformly fractured into polygonal patterns (usually pentagonal or... 

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