Accession Number : AD0818356

Title :   INVESTIGATIONS ON ALKALINE EARTH AZIDES.

Descriptive Note : Final technical rept. May 66-Apr 67,

Corporate Author : TECHNISCHE HOCHSCHULE GRAZ (AUSTRIA) INSTITUT FUER PHYSIKALISCHE CHEMIE

Personal Author(s) : Torkar, Karl

Report Date : MAY 1967

Pagination or Media Count : 182

Abstract : The mechanism of thermal decomposition of anhydrous Ba(N3)2 is discussed from the view of the energy level diagram and the experimental kinetic laws. Nucleation proceeds according to a first order law and is associated to exciton formation. Nucleus growth proceeds via an electron transfer mechanism. For powdered material of uniform particle size the same kinetic laws and activation energies have been found as for single crystals. The t(4)-law is valid the longer the smaller the particles and also the Avrami-Erofeyev equation holds the better the smaller the crystals. Doping of Ba(N3)2 with Na(+) or Cr(3+) (less than 300 ppm) accelerates the decomposition rate without changing the activation energies. The mechanism of decomposition seems to remain unchanged. In the presence of more Cr(3+) (greater than 400 ppm) a new decomposition product was found. A new apparatus is described for determination of the heat of solution of Ba(N3)2. 1,5 H20 below room temperature and thermochemical data of this compound are discussed. Two methods for determination of activity coefficients of Ba(N3)2-solutions are described and a value of alpha = 0,260 is given. This value enables the calculation of free reaction enthalpies. The phase diagram Ca(N3)2 - water is described and two new hydrates were characterized. The lattice parameters, stability ranges, solubilities and thermochemical data of all compounds are given.

Descriptors :   *AZIDES), (*ALKALINE EARTH COMPOUNDS, REACTION KINETICS, NUCLEATION, DOPING, CRYSTALS, PARTICLE SIZE, DECOMPOSITION, TEMPERATURE, AUSTRIA.

Subject Categories : Inorganic Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE