Nickel fluoride, crystal structure

In certain cases, distortion may be imposed by the crystal structure. Nickel and palladium(II) fluorides have the rutile structure (16, 18, 239) in the nickel salt the fluoride octahedron is slightly flattened, whereas in palladium(II) fluoride, it is elongated. The metal-fluorine distances are shown in Table VIII. The fluoride is, incidentally, the only paramagnetic... 

An alternative scenario was put forward based on the crystal structures of urease inhibited by either phosphate, diamidophosphate, or borate (4,5, 28). It gets some support from the kinetic findings for fluoride inhibition of urease (29), as well as from recent model calculations (30, 31). Boric acid, known to be a competitive inhibitor of urease, can be considered a good substrate analogue, since it is isoelectronic with urea and has the same shape and dimension. Bacillus pasteurii could be crystallized in the presence of boric acid. The structure reveals that a molecule of B(OH)3 is symmetrically spanning the nickel ions, replacing Wj, W2,... 

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