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Joint crystallization of KCuAl[PO 4 ] 2 and K(Al,Zn) 2 [(P,Si)O 4 ] 2 : crystal chemistry and mechanism of formation of phosphate‐silicate epitaxial heterostructure
Author(s) -
Yakubovich Olga,
Kiriukhina Galina,
Shvanskaya Larisa,
Volkov Anatoliy,
Dimitrova Olga
Publication year - 2020
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520620005715
Subject(s) - crystallography , crystallization , crystal structure , crystal chemistry , single crystal , crystal (programming language) , x ray crystallography , neutron diffraction , materials science , silicate , chemistry , diffraction , physics , organic chemistry , computer science , optics , programming language
Two novel phases, potassium copper aluminium bis(phosphate), KCuAl[PO 4 ] 2 (I), and potassium zinc aluminium bis(phosphate‐silicate), K(Al,Zn) 2 [(P,Si)O 4 ] 2 (II), were obtained in one hydrothermal synthesis experiment at 553 K. Their crystal structures have been studied using single‐crystal X‐ray diffraction. (I) is a new member of the A + M 2+ M 3+ [PO 4 ] 2 family. Its open 3D framework built by AlO 5 and PO 4 polyhedra includes small channels populated by columns of CuO 6 octahedra sharing edges, and large channels where K + ions are deposited. It is assumed that the stability of this structure type is due to the pair substitution of Cu/Al with Ni/Fe, Co/Fe or Mg/Fe in different representatives of the series. From the KCuAl[PO 4 ] 2 structural features, one may suppose it is a potentially electrochemically active material and/or possible low‐temperature antiferromagnet. In accordance with results obtained from X‐ray diffraction data, using scanning electron microscopy, microprobe analysis and detailed crystal chemical observation, (II) is considered as a product of epitaxial intergrowth of phosphate KAlZn[PO 4 ] 2 and silicate KAlSi[SiO 4 ] 2 components having closely similar crystal structures. The assembly of `coherent intergrowth' is described in the framework of a single diffraction pattern.