Crystal Growth of New Hexahydroxometallates Using a Hydroflux

• Published in: Inorganic chemistry Vol. 52; no. 20; pp. 11723 - 11733
• Main Authors: Chance, W. Michael, Bugaris, Daniel E, Sefat, Athena S, zur Loye, Hans-Conrad
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 21.10.2013
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic400910g

A series of seven compounds, Sr2Mn(OH)6, Ba2Mn(OH)6, Sr2Co(OH)6, Ba2Co(OH)6, Sr2Ni(OH)6, Ba2Ni(OH)6, and Ba2Cu(OH)6, were synthesized using a low-melting hydroflux, a hybrid approach between aqueous hydrothermal and molten hydroxide flux techniques. Crystals of the hexahydroxometallates were obtained by dissolving appropriate amounts of alkaline-earth nitrates or hydroxides and transition-metal oxides, acetates, or chlorides in the hydroflux and reacting at 180–230 °C. The isostructural compounds all crystallize in the monoclinic space group P21/n. The monoclinic structure consists of isolated transition-metal octahedra within a three-dimensional framework of corner- and edge-shared eight-coordinate, alkaline-earth polyhedra. Magnetic susceptibility data show that all compounds are simple paramagnets. Thermogravimetric analysis indicates that these hydroxides lose water between 215 and 350 °C and transform into oxide products, the identity of which depends on the metal cations present in the parent hexahydroxometallates.