Molybdenum trifluoride, structure

Molybdenum hexafluoride. 3,1412 Molybdenum-iron-sulfur complexes, 4,241 Molybdenum oxide amino acid formation prebiotic systems, 6, 872 Molybdenum storage protein microorganisms, 6, 681 Molybdenum telluride, 3, 1431 Molybdenum tetraalkoxides physical properties, 2, 347 Molybdenum tribromide, 3,1330 Molybdenum trichloride, 3,1330 Molybdenum trifluoride, 3, 1330 Molybdenum trihalides, 3, 1330 bond lengths, 3, 1330 magnetic moments, 3,1330 preparation, 3,1330 properties, 3, 1330 structure, 3,1330 Molybdenum triiodide, 3,1330 Molybdenum trioxide complexes, 3, 1379 Molybdenum triselenide, 3, 143)... 

Compound 388 is an acylating agent for electron-deficient alkenes, in a Michael addition process. It is formed by treating molybdenum hexacarbonyl with an organolithium compound, followed by quenching the intermediate 387 with boron trifluoride (equation 104). The structure of 388 (R = Ph) can be elucidated by NMR spectroscopy. Other examples of enantioselective and diastereoselective Michael-type additions involving lithium-containing intermediates in the presence of chiral additives can be found elsewhere in the literature . 

This simple structure originally was assigned by Gutmann and Jdck 122) to the trifluorides of molybdenum and tantalum and later to NbFa... 

The observations made for the trifluorides of molybdenum, niobium and tantalum let it seem doubtful, whether the compound ZrFs, the formula of which was affirmed by chemical analysis, really crystallizes in a ReOs-type structure, as has been tentatively stated 95). The Zr—F-distance of 1.98 A calculated from the reported lattice constant ( =3.96A) is conspicuously small and would 5ueld a Zrs+ ionic radius of 0.65 A only. Therefore the Zr—F—Zr-chains, linear in the ReOs-type, should rather be angled as in the VF8-t e. 

The detailed structures of many trifluorides were reported by Jack and co-workers, from X-ray powder data, which gave very accurate integrated intensities. Although the results for cubic molybdenum and... 

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