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Investigations of phase relations in the system CaONa 2 OK 2 OP 2 O 5
Author(s) -
Schneider M.,
Gildenhaar R.,
Berger G.
Publication year - 1994
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170290516
Subject(s) - lattice constant , superlattice , hexagonal crystal system , diffractometer , lattice (music) , atmospheric temperature range , crystallography , hexagonal lattice , chemistry , materials science , diffraction , analytical chemistry (journal) , crystal structure , thermodynamics , condensed matter physics , physics , optics , optoelectronics , antiferromagnetism , acoustics , chromatography
The lattice constants of the compound Ca 2 NaK(PO 4 ) 2 have been studied at room temperature using an X‐ray powder diffractometer and also in the temperature range from 20 up to 1000 °C by Guinier‐Lenné‐technology. A hexagonal lattice with the parameters a 0 = 5.4367 Å and c 0 = 7.3125 Å and a cell volume of 187.18 Å 3 has been determined for the high temperature phase, existing from 670 °C upward. At temperatures below 670 °C a superlattice structure is formed by tripling the axis a , a ′, and c so that it results in a hexagonal superlattice structure cell with the lattice constants of a 0 = 16.311 Å and c 0 = 21.939 Å and a cell volume of 5054 Å 3 .