Polymorphic Transformations in the K0.945Ag0.055NO3 Single Crystal

• Published in: Crystallography reports Vol. 65; no. 2; pp. 309 - 313
• Main Authors: Nasirov, V. I., Bairamov, R. B., Nasirov, E. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.03.2020; Springer Nature B.V
• Subjects: Crystal Growth; Crystal structure; Crystallography and Scattering Methods; High temperature; Melting points; Parameter modification; Physics; Physics and Astronomy; Room temperature; Single crystals; Transformations; Unit cell; X-ray diffraction
• ISSN: 1063-7745; 1562-689X
• DOI: 10.1134/S1063774520020169

The polymorphic transformations in K 0.945 Ag 0.055 NO 3 are studied by optical spectroscopy and X-ray diffraction. It is established that one structural transformation occurs in this crystal in the temperature range from room temperature to the melting point. The growth of new crystal modification growth is accompanied by the formation and growth of daughter modification nuclei inside the matrix crystal. The equilibrium temperature between modifications II and III ( Т 0 = 393 ± 1 K) and the unit-cell parameters for crystals of these modifications are determined. At room temperature, the orthorhombic modification parameters are a = 5.407 Å, b = 9.156 Å, and c = 6.410 Å; sp. gr. Pnma . The parameters of high-temperature rhombohedral modification are a = 5.405 Å and c = 9.712 Å; sp. gr. . It is established using X-ray diffraction analysis that the II → III polymorphic transformation in K 0.945 Ag 0.055 NO 3 is of the single crystal–single crystal type.