Oxygen-hydrogen bonds, bond lengths

Another inorganic hydrate which has been examined [8] is CuCl8 2H20 which contains a very weak long hydrogen bond, of length about 3 2 A, between chlorine atom and the oxygen atom of a water molecule. The neutron projection shows that the dimensions of the water... 

The alpha helix satisfies this requirement. There are 3.6 to 3.7 amino-acid residues per turn of the helix (about eighteen residues in fi%e turns), and the nitrogen atom of each planar peptide is bonded to the oxygen atom of the third peptide beyond it in the chain by a hydrogen bond with length 2.79 A. 

Table 4 summarizes the Se-O distances in hydrogen selenates. Bond length data are given in colunms for different functions of the oxygen atoms which are listed below in the order of their decreasing influence on the Se-O bond length ... 

The central proton is halfway between the two oxygen atoms of the water molecules, and the ion has C symmetry The hydrogen bonds have lengths of 199 pm and the 0-H bond angle is 174 - The structure probably represents the transition state in the autoprotolysIs of water in which a proton is transferred from one water molecule to a neighbouring one. 

The oxygen-hydrogen bond length is very little changed from that of water, but the carbon-oxygen bond is a bit shorter and stronger than the carbon-carbon bond in ethane (Fig. 6.13). 

The oxygen—hydrogen bond lengths in both hydrogen peroxide (HO—OH) and hydroxylamine (NH2—OH) are the same 96 pm. Explain why. 

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