Structures of the K- and Na-components of two-phase feldspar from Primorskii Krai

The structures of two components of the decomposed solid solution of an alk ali feldspar are refined. These structures exhibit at least two specific fe atures: (1) the complete phase separation into pure K and pure Na phases an d (2) an anomalous distribution of Al atoms over four crystallographically independent positions of silicon-aluminum tetrahedra in the Na-component (d ifferent from its usual distribution). To explain the results obtained, the ideas of synergetics are invoked (the geological history of the specimen i ncludes a powerful explosion, which threw out the material from the volcano to the Earth's surface).