Crystal structure and magnetic properties of a new layered sodium nickel hydroxide phosphate, Na2Ni3(OH)2(PO4)2

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 42; no. 41; pp. 14718 - 14725
• Main Authors: Yakubovich, Olga, Kiriukhina, Galina, Dimitrova, Olga, Volkov, Anatoly, Golovanov, Alexey, Volkova, Olga, Zvereva, Elena, Baidya, Santu, Saha-Dasgupta, Tanusri, Vasiliev, Alexander
• Format: Journal Article
• Language: English
• Published: England 01.10.2013
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c3dt51657a

Mixed sodium nickel hydroxide phosphate, Na 2 Ni 3 (OH) 2 (PO 4 ) 2 , has been synthesized hydrothermally from the system NiCO 3 -Na 4 P 2 O 7 -NaCl-H 2 O. Its monoclinic crystal structure has been determined by single crystal X-ray diffraction: a = 14.259(5), b = 5.695(2), c = 4.933(1) Å, β = 104.28(3)°, space group C 2/ m , Z = 2, ρ c = 3.816 g cm −3 , R = 0.026. The underlying spin model has been characterized in terms of first-principles electronic structure calculations. The compound is formed by alternating layers of [NiO 6 ] octahedra and [NaO 7 ] polyhedra, combined in the [100] direction with tetrahedral [PO 4 ] oxocomplexes and hydrogen bonds. The novel phase is treated as an isostructural variant of the two-dimensional potassium manganese hydroxide vanadate, K 2 Mn 3 (OH) 2 (VO 4 ) 2 , which can be formally obtained by morphotropic substitutions of all positions in the cationic sublattice. The stripe arrangement of Ni 2+ ions ( S = 1) within [NiO 4 (OH) 2 ] layers of Na 2 Ni 3 (OH) 2 (PO 4 ) 2 is unique in the sense that its magnetic topology places it in between widely discussed honeycomb and kagomé lattices. The Na 2 Ni 3 (OH) 2 (PO 4 ) 2 is a low-dimensional magnet, which reaches the short-range correlation regime at T max = 38.4 K and orders antiferromagnetically at T N = 33.4 K. The Na 2 Ni 3 (OH) 2 (PO 4 ) 2 layered crystal structure.