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  2. Tin - Wikipedia

    en.wikipedia.org/wiki/Tin

    Tin is a post-transition metal in group 14 of the periodic table of elements. It is obtained chiefly from the mineral cassiterite, which contains stannic oxide, SnO 2. Tin shows a chemical similarity to both of its neighbors in group 14, germanium and lead, and has two main oxidation states, +2 and the slightly more stable

  3. ISO 31-8 - Wikipedia

    en.wikipedia.org/wiki/ISO_31-8

    Symbol Definition Name Symbol relative atomic mass: A r: Ratio of the average mass per atom of an element to 1/12 of the mass of an atom of the nuclide 12 C one 1 Formerly called atomic/molecular weight. Example: A r (Cl) = 35.453. Both quantities depend on the nuclidic composition. relative molecular mass: M r

  4. Molecular term symbol - Wikipedia

    en.wikipedia.org/wiki/Molecular_term_symbol

    In molecular physics, the molecular term symbol is a shorthand expression of the group representation and angular momenta that characterize the state of a molecule, i.e. its electronic quantum state which is an eigenstate of the electronic molecular Hamiltonian. It is the equivalent of the term symbol for the atomic case.

  5. Atoms in molecules - Wikipedia

    en.wikipedia.org/wiki/Atoms_in_molecules

    In quantum chemistry, the quantum theory of atoms in molecules (QTAIM), sometimes referred to as atoms in molecules (AIM), is a model of molecular and condensed matter electronic systems (such as crystals) in which the principal objects of molecular structure - atoms and bonds - are natural expressions of a system's observable electron density distribution function.

  6. Double bond - Wikipedia

    en.wikipedia.org/wiki/Double_bond

    These effects become more pronounced for the heavier elements. The distannene (Me 3 Si) 2 CHSn=SnCH(SiMe 3) 2 has a tin-tin bond length just a little shorter than a single bond, a trans bent structure with pyramidal coordination at each tin atom, and readily dissociates in solution to form (Me 3 Si) 2 CHSn: (stannanediyl, a carbene analog). The ...

  7. Term symbol - Wikipedia

    en.wikipedia.org/wiki/Term_symbol

    In atomic physics, a term symbol is an abbreviated description of the total spin and orbital angular momentum quantum numbers of the electrons in a multi-electron atom. So while the word symbol suggests otherwise, it represents an actual value of a physical quantity. For a given electron configuration of an atom, its state depends also on its ...

  8. Molecular geometry - Wikipedia

    en.wikipedia.org/wiki/Molecular_geometry

    Some common shapes of simple molecules include: Linear: In a linear model, atoms are connected in a straight line. The bond angles are set at 180°. For example, carbon dioxide and nitric oxide have a linear molecular shape. Trigonal planar: Molecules with the trigonal planar shape are somewhat triangular and in one plane (flat). Consequently ...

  9. Valence (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Valence_(chemistry)

    An alternative definition of valence, developed in the 1920's and having modern proponents, differs in cases where an atom's formal charge is not zero. It defines the valence of a given atom in a covalent molecule as the number of electrons that an atom has used in bonding: [8] [9] [10] [11]