Glossary – T
THF: Abbreviation of tetra-hydro-furan (see Furan), a common solvent in organic reactions.
TMS: Abbreviation of tri-methyl-silane (-SiMe3).
Tautomerism: Some functional groups are related to other functional groups by a simple H shift – they are tautomers, and conversion between them is called tautomerism. The main example of this is keto-enol tautomerism.
Template Effect: Complexation of a ligand to a metal ion stabilizes one component of a mixture, shifting the equilibrium in that mixture in favour of production of the metal complex.
Term Symbols: This is a way of describing the spin, orbital, and total angular momentum of a species.
Tertiary: See also secondary. A carbon centre described as tertiary has one functional group and three other carbons attached to it. A nitrogen centre is tertiary if it has three carbons bonded to it.
Thermal energy, kT: The energy available from the thermal motion of particles at a particular temperature.
Thermal motion: The oscillation of particles about a mean position that occurs when they possess energy.
Thermodynamic Control: A reaction under thermodynamic control will produce, in the greatest proportion the most stable possible product.
Thermodynamic Product: If multiple products are possible in a reaction, the thermodynamic product is the most stable of those. Will be formed if the reaction is under thermodynamic control. See also kinetic product.
Torque: The rotational analogue of force, being given by the force multiplied by its perpendicular distance from the axis of rotation.
Transition Frequency: For a given transition with energy gap ΔE between the two states, the frequency such that ΔE = hν.
Transition State: A state during a reaction that the reactants may pass through – a high energy state that will not be isolated. Compare with intermediate.
Trans: Two substituents that are trans to each other are on opposite sides of a bond.
Trigonal Bipyramid: A five-coordinate polyhedron.
Trigonal Planar: A flat triangle shape;
Triple point: A point at which three phase boundaries meet. It is most commonly applied to the point at which solid, liquid and vapour phases simultaneously coexist. It is a characteristic of a particular substance.
Triplet States: This is a state which has two electrons with parallel spins.
Tumbling: See Molecular tumbling.
Tunnelling: Penetration of particles into areas of potential that classically they would be forbidden to enter.