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Bond Type of bond Specific type of bond Absorption peak (cm −1) Appearance C─H alkyl methyl 1260 strong 1380 weak 2870 medium to strong 2960 medium to strong methylene: 1470 strong 2850 medium to strong 2925 medium to strong methine: 2890 weak vinyl: C═CH 2: 900 strong 2975 medium 3080 medium C═CH 3020 medium monosubstituted alkenes ...
Certain hydrogen bonds - improper hydrogen bonds - show a blue shift of the X−H stretching frequency and a decrease in the bond length. [26] H-bonds can also be measured by IR vibrational mode shifts of the acceptor.
A molecular vibration is a periodic motion of the atoms of a molecule relative to each other, such that the center of mass of the molecule remains unchanged. The typical vibrational frequencies range from less than 10 13 Hz to approximately 10 14 Hz, corresponding to wavenumbers of approximately 300 to 3000 cm −1 and wavelengths of approximately 30 to 3 μm.
In both liquid water and ice clusters, low-frequency vibrations occur, which involve the stretching (TS) or bending (TB) of intermolecular hydrogen bonds (O–H•••O). Bands at wavelengths λ = 50-55 μm or 182-200 cm −1 (44 μm, 227 cm −1 in ice) have been attributed to TS, intermolecular stretch, and 200 μm or 50 cm −1 (166 μm ...
Although hydrogen bonding is a relatively weak attraction compared to the covalent bonds within the water molecule itself, it is responsible for several of the water's physical properties. These properties include its relatively high melting and boiling point temperatures: more energy is required to break the hydrogen bonds between water molecules.
Bond dissociation energy for the carbon monoxide (CO) triple bond, alternatively stated: 1072 kJ/mol; 11.11eV per molecule. [21] This is the strongest chemical bond known. 2.18×10 −18 J: Ground state ionization energy of hydrogen (13.6 eV) 10 −17 2–2000×10 −17 J Energy range of X-ray photons [8] 10 −16 10 −15: femto-(fJ) 3 × 10 ...
The alpha helix is also commonly called a: Pauling–Corey–Branson α-helix (from the names of three scientists who described its structure); 3.6 13-helix because there are 3.6 amino acids in one ring, with 13 atoms being involved in the ring formed by the hydrogen bond (starting with amidic hydrogen and ending with carbonyl oxygen)
Molecular geometries can be specified in terms of 'bond lengths', 'bond angles' and 'torsional angles'. The bond length is defined to be the average distance between the nuclei of two atoms bonded together in any given molecule. A bond angle is the angle formed between three atoms across at least two bonds.