An electron diffraction determination of the molecular structure of manganese pentacarbonyl hydride in the vapour phase

The structure of manganese pentacarbonyl hydride, HMn(CO)5, has been determined by the sector-microphotometer method of electron diffraction. The results are consistent with a C 4v model; the mean Mn-C bond length is 1.860 ± 0.004 Å, the mean C-O bond length is 1.139 ± 0.004 Å, and the angle C(ax)MnC(eq) is 96.4±1.0°. A value of 1.50 ± 0.07 Å is obtained for the Mn-H bond length; the possible effects of random and systematic errors on this value are discussed.