MOESSBAUER INVESTIGATION OF STATIC-DISORDER CRYSTALLINE MEDIA Ⅱ. CRYSTAL-CHEMISTRY ASPECTS OF TETRAGONAL AND TRIGONAL GERMANATES (GEHLENITE AND GALLATE STRUCTURES)

摘要

The second part of the static-disordered crystalline media by ~(57)Fe Moessbauer investigation technique, contains a detailed discussion of some crystal chemistry aspects of the new syhtetic ferrigehlenits and ferri and/or trivalent lanthanides gallates. On this line, the effect of the type and size of the lanthanide ions in these structures on the unit cell parameters, on the chemical bond energy and on the presence of the superexchanges interactions is pointed out and discussed.