Accession Number : AD0428582


Title :   NMR STUDIES OF PHASE TRANSITIONS. II. NACN.,


Corporate Author : ILLINOIS UNIV URBANA NOYES CHEMICAL LAB


Personal Author(s) : Coogan,C K ; Gutowsky,H S


Report Date : 31 Dec 1963


Pagination or Media Count : 23


Abstract : The Na-23 nuclear magnetic resonance absorption has been observed in the cubic phase of polycrystalline NaCN between about 15 C and 170 C, but could not be detected in the orthorhombic phase which forms below 10.5 C. The electric field gradients involved are attributed to the electric dipoles of the CN-ions and the temper ature dependence and to the averaging out of the gradients by thermally activated reorientations of the CN-ions. The reorientations are deemed responsible for the existence of a cubic phase. They are treated as a random walk problem yielding algebraic expressions by means of which an activation energy of 6 kcal/mole is obtained. (Author)


Descriptors :   *CRYSTAL STRUCTURE , *PHASE STUDIES , *SODIUM COMPOUNDS , TRANSITION TEMPERATURE , NUCLEAR MAGNETIC RESONANCE , CYANIDES , CRYSTAL LATTICES , DIPOLE MOMENTS , NUCLEATION , SYMMETRY(CRYSTALLOGRAPHY) , HEAT OF ACTIVATION , QUADRUPOLE MOMENT


Distribution Statement : APPROVED FOR PUBLIC RELEASE