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  2. Halogen bond - Wikipedia

    en.wikipedia.org/wiki/Halogen_bond

    Most biological macromolecules contain few or no halogen atoms. But when molecules do contain halogens, halogen bonds are often essential to understanding molecular conformation. Computational studies suggest that known halogenated nucleobases form halogen bonds with oxygen, nitrogen, or sulfur in vitro.

  3. Halogen - Wikipedia

    en.wikipedia.org/wiki/Halogen

    The group of halogens is the only periodic table group that contains elements in three of the main states of matter at standard temperature and pressure, though not far above room temperature the same becomes true of groups 1 and 15, assuming white phosphorus is taken as the standard state. [n 1] All of the halogens form acids when bonded to ...

  4. Bond energy - Wikipedia

    en.wikipedia.org/wiki/Bond_energy

    It is sometimes called the mean bond, bond enthalpy, average bond enthalpy, or bond strength. [ 1 ] [ 2 ] [ 3 ] IUPAC defines bond energy as the average value of the gas-phase bond-dissociation energy (usually at a temperature of 298.15 K) for all bonds of the same type within the same chemical species.

  5. Enthalpy change of solution - Wikipedia

    en.wikipedia.org/wiki/Enthalpy_change_of_solution

    The enthalpy of solution is most often expressed in kJ/mol at constant temperature. The energy change can be regarded as being made up of three parts: the endothermic breaking of bonds within the solute and within the solvent, and the formation of attractions between the solute and the solvent.

  6. Iodine compounds - Wikipedia

    en.wikipedia.org/wiki/Iodine_compounds

    The halogens form many binary, diamagnetic interhalogen compounds with stoichiometries XY, XY 3, XY 5, and XY 7 (where X is heavier than Y), and iodine is no exception. Iodine forms all three possible diatomic interhalogens, a trifluoride and trichloride, as well as a pentafluoride and, exceptionally among the halogens, a heptafluoride.

  7. Benson group increment theory - Wikipedia

    en.wikipedia.org/wiki/Benson_group_increment_theory

    First-order approximation. Additivity of bond properties. Second-order approximation. Additivity of group properties. These approximations account for the atomic, bond, and group contributions to heat capacity (C p), enthalpy (ΔH°), and entropy (ΔS°). The most important of these approximations to the group-increment theory is the second ...

  8. Standard enthalpy of reaction - Wikipedia

    en.wikipedia.org/wiki/Standard_enthalpy_of_reaction

    Standard enthalpy of combustion is the enthalpy change when one mole of an organic compound reacts with molecular oxygen (O 2) to form carbon dioxide and liquid water. For example, the standard enthalpy of combustion of ethane gas refers to the reaction C 2 H 6 (g) + (7/2) O 2 (g) → 2 CO 2 (g) + 3 H 2 O (l).

  9. Oxohalide - Wikipedia

    en.wikipedia.org/wiki/Oxohalide

    For example, chromyl chloride is hydrolyzed to chromate in the reverse of the synthetic reaction, above. The driving force for this reaction is the formation of A-O bonds which are stronger than A-Cl bonds. This gives a favourable enthalpy contribution to the Gibbs free energy change for the reaction [3] Many oxohalides can act as Lewis acids.