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  2. List of character tables for chemically important 3D point groups

    en.wikipedia.org/wiki/List_of_character_tables...

    These groups are characterized by i) an n-fold proper rotation axis C n; ii) n 2-fold proper rotation axes C 2 normal to C n; iii) a mirror plane σ h normal to C n and containing the C 2 s. The D 1 h group is the same as the C 2 v group in the pyramidal groups section.

  3. Zinc compounds - Wikipedia

    en.wikipedia.org/wiki/Zinc_compounds

    [zn(h 2 o) 6] 2+ ⇌ [zn(h 2 o) 5 (oh)] + + h + Hydrolysis explains why basic salts such as basic zinc acetate and basic zinc carbonate, Zn 3 (OH) 4 (CO 3 )•H 2 O are easy to obtain. The reason for the hydrolysis is the high electrical charge density on the zinc ion, which pulls electrons away from an OH bond of a coordinated water molecule ...

  4. Organozinc chemistry - Wikipedia

    en.wikipedia.org/wiki/Organozinc_chemistry

    A polar covalent bond exists between carbon and zinc, being polarized toward carbon due to the differences in electronegativity values (carbon: 2.5 & zinc: 1.65). The dipole moment of symmetric diorganozinc reagents can be seen as zero in these linear complexes, which explains their solubility in nonpolar solvents like cyclohexane .

  5. Standard enthalpy of formation - Wikipedia

    en.wikipedia.org/wiki/Standard_enthalpy_of_formation

    For many substances, the formation reaction may be considered as the sum of a number of simpler reactions, either real or fictitious. The enthalpy of reaction can then be analyzed by applying Hess' law, which states that the sum of the enthalpy changes for a number of individual reaction steps equals the enthalpy change of the overall reaction.

  6. Zinc–copper couple - Wikipedia

    en.wikipedia.org/wiki/Zinc–copper_couple

    Zinc–copper couple is an alloy of zinc and copper that is employed as a reagent in organic synthesis. The “couple” was popularized after the report by Simmons and Smith, published in 1959, on its application as an activated source of zinc required for formation of an organozinc reagent in the Simmons–Smith cyclopropanation of alkenes ...

  7. Proofs of trigonometric identities - Wikipedia

    en.wikipedia.org/wiki/Proofs_of_trigonometric...

    Then multiplying the numerator and denominator inside the square root by (1 + cos θ) and using Pythagorean identities leads to: ⁡ = ⁡ + ⁡. Also, if the numerator and denominator are both multiplied by (1 - cos θ), the result is:

  8. Zinc picolinate - Wikipedia

    en.wikipedia.org/wiki/Zinc_picolinate

    Zinc picolinate (or ZnPic) is the zinc coordination complex derived from picolinic acid and zinc(II). It has the formula Zn(NC 5 H 4 CO 2 ) 2 (H 2 O) 2 . The complex adopts an octahedral molecular geometry , containing two bidentate picolinate ligands (conjugate base of picolinic acid) and two aquo ligands .

  9. List of trigonometric identities - Wikipedia

    en.wikipedia.org/wiki/List_of_trigonometric...

    Ptolemy's theorem states that the sum of the products of the lengths of opposite sides is equal to the product of the lengths of the diagonals. When those side-lengths are expressed in terms of the sin and cos values shown in the figure above, this yields the angle sum trigonometric identity for sine: sin(α + β) = sin α cos β + cos α sin β.