Tetragonal-antiprismatic coordination of transition metals in intermetallic compounds: ω1-Mn6Ga29 and its structuralrelationships

The new phase ω1-Mn6Ga29 was synthesised in single-crystal form from the elements applying the high-temperature centrifugation-aided filtration technique. The crystal structure was determined using diffraction data collected from a twinned specimen: a new prototype, space group P  1¯; a=6.3114(2) Å, b=9.9557(3) Å, c=18.920(1) Å, α=90.473(1)°, β=90.847(1)°, γ=90.396(1)°; R1=0.047, wR2=0.117 for 317 variable parameters and 7346 observed reflections; twinning matrix 0 0 –13, 0 −1 0, −3 0 0; twin domains ratio 0.830(3):0.170. All manganese atoms in the crystal structure of ω1-Mn6Ga29 are coordinated exclusively by Ga forming distorted tetragonal antiprisms. The monocapped [MnGa8+1] antiprisms condense into pairs by sharing their pseudo-quadratic faces and are interconnected via common apexes and edges to form a 3D framework. The relationship between the crystal structures of ω1-Mn6Ga29 and CuAl2, α-, β-CoSn3, PtSn4, Ti4MnBi2, PdGa5, Rh3Ga16, Rh4Ga21, Al7FeCu2, Co2Al9, and RhBi4 is discussed.

Graphical abstractω1-Mn6Ga29 was synthesised applying the high-temperature centrifugation-aided filtration technique. The crystal structure was determined using diffraction data collected from a twinned specimen: a new prototype, space group P  1¯ ; a=6.3114(2) Å, b=9.9557(3) Å, c=18.920(1) Å, α=90.473(1)°, β=90.847(1)°, γ=90.396(1)°. The basic building unit of the structure is the monocapped distorted tetragonal antiprism [MnGa8+1]. These antiprisms condense into pairs by sharing their pseudo-quadratic faces and are interconnected via common apexes and edges to form a 3D framework.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The crystals of new phase ω1-Mn6Ga29 are grown from Ga flux. ► Single-crystal diffraction data is obtained from the twinned specimen. ► The ω1-Mn6Ga29 structure represents a new prototype. ► Main building unit is distorted monocapped tetragonal antiprism [MnGa8+1]. ► The structural peculiarities of ω1-Mn6Ga29 and related structures are discussed.