Symbol θ. The unique tempera­ture at which the attractions and repulsions of a polymer in a solution cancel each other. It is analogous to the Boyle temperature of a nonideal gas. A polymer solution at the Flory temperature is called a theta (θ) solu­tion. At the Flory temperature the virial coefficient B, associated with the

 A type of ionic crystal structure in which the cations have an expanded face-centered cubic arrangement with the anions occupy­ing both types of tetrahedral hole. The cations have a coordination number of 8 and the anions have a coordination number of 4. Examples of compounds with this structure are CaF2, BaCl2, and PbO2. The antifluorite

A benzodiazepine used medically in some countries as a powerful hypnotic, sedative, and muscle relaxant. It was marketed in the US under the trade name Rohyp­nol. Flunitrazepam has become notorious as a so-called ‘date rape’ drug. It is quickly eliminated from the body, difficult to detect, and causes amne­sia, so that victims cannot remember events