Synthesis and crystal structure of the high-pressure iron borate {alpha}-FeB{sub 2}O{sub 4}

• Published in: Journal of solid state chemistry Vol. 181; no. 8
• Main Authors: Knyrim, Johanna S., Huppertz, Hubert
• Format: Journal Article
• Language: English
• Published: United States 15.08.2008
• Subjects: BORATES; CATIONS; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; IRON COMPOUNDS; LATTICE PARAMETERS; LAYERS; MONOCLINIC LATTICES; ORTHORHOMBIC LATTICES; OXYGEN; PRESSURE RANGE GIGA PA; PRESSURE RANGE MEGA PA 10-100; SPACE GROUPS; SYNTHESIS; TEMPERATURE RANGE 1000-4000 K
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2008.05.016

The high-pressure iron borate {alpha}-FeB{sub 2}O{sub 4} was synthesized under high-pressure and high-temperature conditions in a Walker-type multianvil apparatus at 7.5 GPa and 1100 deg. C. The monoclinic iron borate crystallizes with eight formula units in the space group P2{sub 1}/c with the lattice parameters a=715.2(2), b=744.5(2), c=862.3(2) pm, and {beta}=94.71(3){sup o}. The compound is built up exclusively from corner-sharing BO{sub 4}-tetrahedra, isotypic to the monoclinic phases {beta}-SrGa{sub 2}O{sub 4}, CaAl{sub 2}O{sub 4}-II, and CaGa{sub 2}O{sub 4}. Additionally, the structure is closely related to the orthorhombic compound BaFe{sub 2}O{sub 4}. The structure consists of layers of six-membered rings, which are interconnected to a three-dimensional network. The iron cations are coordinated by six and seven oxygen atoms. Next to synthesis and crystal structure of the new high-pressure borate, structural coherences to other structure types are discussed. - Abstract: High-pressure/high-temperature synthesis (multianvil technique) led to the new phase {alpha}-FeB{sub 2}O{sub 4}, which is exclusively built up from corner-sharing BO{sub 4}-tetrahedra, isotypic to the monoclinic phases {beta}-SrGa{sub 2}O{sub 4}, CaAl{sub 2}O{sub 4}-II, and CaGa{sub 2}O{sub 4}. Display Omitted.