FTIR spectra of microcrystalline samples of 11 metal ion salt hydrates of a variety of weakly coordinating fluoroanions are reported. The compounds studied were Li(H2O)(4)(Al(OC(CF3)(3))(4)), Li(H2O)(B(3,5-C6H3(CF3)(2))(4)), Li(H2O)(n)(Ga-(C2F5)(4)), Li(H2O)(PF6), Li-2(H2O)(2)(TiF6), Li-2(H2O)(4)(B12F12), Na(H2O)(PF6), Na-2(H2O)(2)(B12F12), K-2(H2O)(2)(B12F12), Rb-2(H2O)(2)(B12F12), Cs-2(H2O)(B12F12), and their partially or completely deuterated isotopologs and isotopomers. The O-D center dot center dot center dot F hydrogen bonds in Li(HOD)(H2O)(3)(Al(OC(CF3)(3))(4)) (nu(OD) = 2706 cm(-1)), Li(HOD)(B(3,5-C6H3(CF3)(2))(4)) (nu(OD) = 2705 cm(-1)), and Li(HOD)(H2O)(n)(Ga-(C2F5)(4)) (nu(OD) = 2697 cm(-1)) rival HOD absorbed in polyvinylidene difluoride (nu(OD) = 2696 cm(-1)) and HOD center dot center dot center dot FCH3 in a frozen Ar matrix (nu(OD) = 2685 cm(-1)) for the weakest hydrogen bonds between a water molecule and an F atom in any compound. As weak as they are, minor differences in O-H center dot center dot center dot F hydrogen bonds in the same fluoroanion salt can be distinguished spectroscopically. Uncoupled HOD molecules in asymmetric F center dot center dot center dot HOD center dot center dot center dot F' hydrogen bonding environments in Rb+, Cs+, Mg2+, and Co2+ hydrates of B12F122- gave rise to two observable nu(OD) bands even though the two R(O center dot center dot center dot F) distances differ by only 0.010(4) angstrom (Mg2+), 0.033(2) angstrom (Co2+), 0.074(4) angstrom (Rb+), and 0.106(6) angstrom (Cs+). A plot of nu(OD) for hydrates with a single uncoupled HOD molecule per metal ion (e.g., Li(HOD)(H2O)(3)(Al(OC(CF3)(3))(4))) vs R(O center dot center dot center dot F) distance from single-crystal X-ray or neutron diffraction structures was prepared. The nu(OD) values range from 2305 to 2706 cm(-1) and the R(O center dot center dot center dot F) distances range from 2.58 to 3.17 angstrom. The plot consists of 53 {nu(OD), R(O center dot center dot center dot F)} data points, 23 of which are new and have nu(OD) > 2600 cm(-1), in contrast to a 1994 nu(OD) vs R(O center dot center dot center dot F) plot with 28 data points, none of which had nu(OD) > 2600 cm(-1). There is a clear and significant difference between the new nu(OD) vs R(O center dot center dot center dot F) plot and a literature nu(OD) vs R(O center dot center dot center dot O) plot for hydrates containing O-D center dot center dot center dot O hydrogen bonds. For a given nu(OD) stretching frequency, the exponential regression curves show that R(O center dot center dot center dot F) is typically 0.1-0.2 angstrom shorter than R(O center dot center dot center dot O), in harmony with the lower basicity and smaller size of F atoms vs O atoms.