MAKE A MEME
View Large Image
| View Original: | Lipscomb-NMR-hexaborene-B6H10.png (1552x1232) | |||
| Download: | Original | Medium | Small | Thumb |
| Courtesy of: | commons.wikimedia.org | More Like This | ||
| Keywords: Lipscomb-NMR-hexaborene-B6H10.png en Nuclear Magnetic Resonance NMR spectrum and structure of hexaborane B<sub>6</sub>H<sub>10</sub> NMR Interpretation of hexaborane 12 8 MHz range right A simple example of the <b>chemical shift</b> is the a and b doublets pairs of peaks A and b are two groups of boron atoms in different electronic environments which place the a doublet to the right of the b doublet in the spectrum The relative peak heights of the a and b doublets suggest a 1 5 ratio of borons in one environment to borons in another environment This suggests combined with the molecular weight of the molecule <ul> <li>5 boron atoms in one environment b and <li>1 boron atom in another environment a </ul> which in turn suggests a pyramidal structure which does appear in the atomic diagram 40 MHz range left a suggests a hydrogen at the apex which is in the atomic diagram sticking straight up b suggests hydrogens bonded to one boron each which are in the atomic diagram sticking straight out from the edges c suggests other bridge hydrogens which is to say hydrogens in the middle of a boron-hydrogen-boron bonding arrangement like a hydrogen bridge between two boron shores which are in a ring around the atomic diagram Williams1959 History X-ray diffraction was needed to be sure of the structure Hirshfeld1958 More complex molecules are more challenging although in some cases common subgroups of atoms produce characteristic spectral patterns which can be recognized References Williams1959 Wiliams R E Gibbins S G and Shapiro I J Chem Phys 30 333 1959 Hirshfeld1958 Hirshfeld F L Eriks K Dickerson R E Lippert E L and Lipscomb W N Molecular and Crystal Structure of B<sub>6</sub>H<sub>10</sub> J Chem Phys 28 56 1958 The two papers above reviewed in Eaton GR Lipscomb WN 1969 NMR Studies of Boron Hydrides and Related Compounds W A Benjamin Inc See author list for the two papers above 2011-02-17 Research paid for by a U S Government grant in the public domain PD-USGov Boranes NMR spectra William Lipscomb | ||||
