NMR timescale: The NMR timescale for an interconversion is the timescale judged relative to the difference between the frequencies of nuclei in the start and finish situations. NMR: See Nuclear Magnetic Resonance. Nearest Neighbour: The atom of closest approach to a given atom in a solid. Neighbouring Group Effect: The effect that local groups of … Read more
Macrocyclic Effect: A complex formed with a closed ring ligand is more stable than its open chain analogue. Madelung Constant: This is the factor by which the ionic charges must be scaled to allow for the different arrangements of ions in different structures. It is determined only by the geometry of the crystal. Madelung Energy: … Read more
LCAO: See Linear Combination of Atomic Orbitals. LCFT: See Ligand and Crystal Field Theories. LFSE: See Ligand Field Stabilization Energy. LUMO: See Lowest Unoccupied Molecular Orbital. Labile: A species is labile if it has a high kinetic reactivity. Larmor frequency: The frequency at which a magnetic nucleus comes into resonance in a magnetic field of … Read more
Kapustinskii Equation: This is a generalized form of the Born-Lande equation, such that an average value of the Madelung constant is taken so that the use of this equation to calculate lattice energies is independent of structure. Kekulé Structure: An early proposal for the structure of benzene, consisting of alternating double and single bonds in … Read more
Jahn-Teller Effect: This states that “when the ground state electronic configuration of a non-linear compound is degenerate, the compound will distort so that the degeneracy is removed”.
Ideal Gas: See Perfect Gas Ideal Solution: A solution in which there are no interactions between the solvent and the solute particles. Induction: A more electronegative element will inductively withdraw electron density along a σ bond, polarising the bond. This will stabilise carbanions, because the negative charge is somewhat pulled away from the carbon centre … Read more
HOMO: See Highest Occupied Molecular Orbital. HSAB: See Hard and Soft Acids and Bases theory. Half angle: In a right cone, the angle between the edge of the cone and its perpendicular axis. Half-Reaction: The reaction describing the reduction of a given species and balanced by electrons, protons, hydroxide ions and water molecules. Half-cell: An … Read more
Galvanic cell: An electrochemical cell for which the cell reaction as written is spontaneous. It thus produces electricity as a result. Gas Constant (R): Having a numerical value equal to 8.314 kJmol-1K-1, the gas constant is effectively a molarheat capacity. Gauche: Where non eclipsed groups with lone pairs are not unaligned, but trans. Gibb’s Free … Read more
Face Centered Cubic Array: A close packed array of spheres which give a structure with spheres at each of the corners and in the center of each of the faces. Fast Ion Conductor: This is an ionic compound in which the conductivity is discontinuous, with it suddenly increasing due to a phase transition which results … Read more
E (Entgegen): “E” stands for “entgegen” which is German for “opposite”. This term is used to describe the geometry of species (for example those attached to a double bond) if they are on opposite sides – i.e. trans. EXAFS: See Extended X-ray Absorption Fine Structure. Eclipsed: A term used in describing conformations. This means that … Read more