CHEM01200604005 A. K. Pathak - Homi Bhabha National Institute

Fig. 6.1-VA having distorted trigonal bipyramidal arrangement with five N atoms around
K atom. The planar arrangement of five N atoms around K atom is least stable conformer
among the three and shown in Fig. 6.1-VC. The solvent ammonia molecules are bound
by each other with weak intermolecular hydrogen bonding. In structure 6.1-VB, the three
NH 3 molecules in a plane approached to K from one side and two NH 3 molecules in
approached to K from opposite side. The conformers shown in Fig. 6.1-VB and 6.1-VC is
3.20 and 0.89 kcal/mol, respectively less stable than the most stable conformer, VA. The
most stable minimum energy structure of K.6NH 3 cluster is displayed in Fig. 6.1-VIA
having distorted octahedral arrangement with six N atoms around the central K atom.
Fig.6.1-VI B showing pentagonal pyramidal arrangement of N atoms around K atom and
0.36 kcal/mol less stable compare to the most stable structure. The least stable conformer
of hexa ammoniated potassium cluster is shown in Fig. 6.1-VI C and having planar
arrangement of six NH 3 molecules around K atom. The NH 3 molecules are connected by
six weak intermolecular hydrogen bonds. This structure is 4.07 kcal/mol less stable than
the most stable conformer.
I II III
Fig. 6.1 (Contd.)
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