The Microwave Spectrum and Structure of NSF3


The Microwave Spectrum and Structure of NSF3https://pubs.acs.org/doi/pdf/10.1021/ja00862a003by WH Kirchhoff - ‎1962 - ‎Cited by 63 - ‎Related ar...
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LVILLIAN H. KIRCHHOFF AND E. BRIGHT Ur1~s0h',J R .

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leads to a vanishing of the exchange integral. Another possible promotion is from the non-bonding level to a u*-antibonding state. This promotion should lead to a non-vanishing of the exchange integral. ,4 comparison of the nitrogen splittlng in NH2 with that of NH3+, recently observed by Cole, l 3 however, indicates that this contribution is small. Karplus and Fraenkel have pointed out that the spin polarization of the 1s electrons will (13) T. Cole, J . Chem. P h y s . , 35, 1169 ( l Y C 1 )

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also contribute to Q1of equation 1. No value for this contribution is available a t the present time for nitrogen atoms in heterocyclic molecules. Conclusion.-The use of equation 1 in relating spin densities and coupling constants of nitrogen atoms in heterocyclic negative ions appears to be substantiated. The Hiickel theory is a reasonable approximation for these ions. Acknowledgment.-I wish to thank Professor A. Streitwieser for helpful discussions.

MALLINCKRODT CHEMICAL LABORATORY, HARVARD UNIVERSITY, CAMBRIDGE, MASS.1

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The Microwave Spectrum and Structure of

NSF31a

BY WILLIAMH. KIRCHEIOFF'~ AND E. BRIGHTWILSON, JR. RECEIVED AUGUST25, 1961 The action of AgF2 on S4Na in CClr produces a gaseous compound, KSF3, the structure of which has been in some doubt. .i pure sample was prepared. Fragments in the mass spectrum show that the molecular structure is probably S--SF/F as \F most recently claimed by Glemser. The microwave spectrum was studied in the region 8000 t o 60,000 mc. with a conventional Stark modulated spectrograph. The spectrum has the simplicity and first order Stark effects characteristic of a symmetric top. From lines assigned t o the normal and also t o the 34San$ 15h7species occurring in natural abundance, the following set of structural parameters was obtained: d ( S K ) = 1.416 A , , d(S-F) = 1.552 A. and