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Actinium Trifluoride
Actinium(III) fluoride (AcF3) is an inorganic compound, a salt of actinium and fluorine. Synthesis Actinium fluoride can be prepared in solution or by a solid-state reaction. In the first method, actinium hydroxide is treated with hydrofluoric acid and the product precipitates: :Ac(OH)3 + 3HF -> AcF_3(v) + 3H2O In the solid-state reaction, actinium metal is treated with hydrogen fluoride gas at 700 °C in a platinum crucible.Meyer, Gerd and Morss, Lester R. (1991) ''Synthesis of lanthanide and actinide compounds.'' Springer. . pp. 87–88 Properties Actinium fluoride is a white solid that reacts with ammonia at 900–1000 °C to yield an actinium oxyfluoride: :AcF3 + 2NH3 + H2O -> AcOF + 2NH4F While lanthanum oxyfluoride is easily formed by heating lanthanum fluoride Lanthanum trifluoride is a refractory ionic compound of lanthanum and fluorine. The LaF3 structure Bonding is ionic with lanthanum highly coordinated. The cation sits at the center of a trigon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhombohedral
In geometry, a rhombohedron (also called a rhombic hexahedron or, inaccurately, a rhomboid) is a three-dimensional figure with six faces which are rhombus, rhombi. It is a special case of a parallelepiped where all edges are the same length. It can be used to define the rhombohedral lattice system, a Honeycomb (geometry), honeycomb with rhombohedral cells. A cube is a special case of a rhombohedron with all sides square. In general a ''rhombohedron'' can have up to three types of rhombic faces in congruent opposite pairs, ''C''''i'' symmetry, Order (group theory), order 2. Four points forming non-adjacent vertices of a rhombohedron necessarily form the four vertices of an orthocentric tetrahedron, and all orthocentric tetrahedra can be formed in this way. Rhombohedral lattice system The rhombohedral lattice system has rhombohedral cells, with 6 congruent rhombic faces forming a trigonal trapezohedron: : Special cases by symmetry * Cube: with Octahedral symmetry, Oh symm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
