Home – Home – Jornals – Journal of Structural Chemistry 2011 number 3

By means of the formula that characterizes the correlation between the parameters of XH…Y linear fragments ( are the bond lengths in free molecules, b^XHX, b^YHY are the dimensional coefficients) r^XX(r^XH) and r^XY(r^YH) dependences are obtained. Given the length of a hydrogen bridge formed by O, N, and F atoms, they enable us to find the proton position in the bridge. The definition "a quasi-symmetric hydrogen bond," based on the invariance of the r^XX distance when the proton shifts by 0.1 Å, is established to be applicable to ОНО, FHF, NHN, and ClHCl fragments. It is shown that the hydrogen bridge length remains almost constant (exceeds the minimum length by no more than 0.1 Å) if its bond orders are above 0.1. Here the displacement of the central proton can reach 0.2-0.3 Å.