Herbert Schäfer

Structural characterization of new ternary compounds of uranium and cerium

Abstract The new ternary uranium and cerium compounds UCu4Al8, U2Cu7Al10, URu2Si2, CeCu6.5Al6.5, CeCu2Sn1.9 and CeZn2Al2 have been prepared and structurally characterized.

Neue polytelluridostannate (IV): Zur kenntnis von Rb2SnTe5 und Cs4Sn2Te7

The new compound Rb2SnTe5 crystallizes in the tetragonal system, space group I4cm (No. 108) with the lattice constants 866.6(3) pm, c=1545.1 (5) pm,ca = 1:783 SnTe4-tetrahedra and planar Te5-groups are connected by common edges to strings, separated by the Rb-ions. The new compound Cs4Sn2Te7 crystallizes in the monoclinic system, space group C2c (No. 15) with the lattice constants a=1649.1(7) pm, b 786.0(3) pm, c=1903.6(7) pm, B=105.5(1)o Two SnTe4-tetrahedra are connected by a common corner and a Te-Te-bridge to a five membered ring, forming a Sn2Te74− anion.

Beiträge zu den stabilitätskriterien der BaCuSn2-struktur: Die verbindungen LaCu0,56Sn2, LaNi0,74Sn2, LaCo0,52Sn2, LaFe0,34Sn2 und BaCuSn2

Zusammenfassung Die neuen Verbindungen LaCu 0,56 Sn 2 , LaNi 0,74 Sn 2 , LaCo 0,52 Sn 2 und LaFe 0,34 Sn 2 kristallisieren orthorhombisch (Raumgruppe, Cmcm ) in der BaCuSn 2 -Struktur mit folgenden Gitterkonstanten: LaCu 0,56 Sn 2 , a = 453,0 ± 0,1 pm, b = 1834,0 ± 0,4 pm, c = 446,0 ± 0,1 pm; LaNi 0,74 Sn 2 , a = 452,6 ± 0,1 pm, b = 1779,0 ± 0,4 pm, c = 451,0 ± 0,1 pm; LaCo 0,52 Sn 2 , a = 458,5 ± 0,1 pm, b = 1741,4 ± 0,4 pm, c = 452,0 ± 0,1 pm; LaFe 0,34 Sn 2 , a = 461,0 ± 0,1 pm, b = 1723,0 ± 0,4 pm, c = 449,0 ± 0,1 pm. LaCu 2 Sn 2 kristallisiert tetragonal (Raumgruppe, P4/nmm ) in der CaBe 2 Ge 2 -Struktur mit a = 446,4 ± 0,1 pm, c = 1050,9 ± 0,2 pm und c a = 2,354 .

K2GeTe4, ein pertelluridogermanat mit kettenstruktur

The new compound K2GeTe4 crystallizes in the monoclinic system, space group P21c (No 14) with lattice constants a = 1270.3 ± 0.6 pm, b = 868.0 ± 0.4 pm, c = 982.9 ± 0.4 pm, s = 104.8 ± 0.1°. In the structure there are GeTe4-tetrahedra, connected by Te2-bridges to infinite chains.

CaMnxAl2−x und CaMn4Al8, Ternäre vertreter der MgNi2- beziehungsweise ThMn12-Struktur

The new compound CaMnxAl2−x (with 0.16 ⩽ x ⩽ 0.32) crystallizes in the hexagonal system (space group, P63mmc) in the MgNi2 structure with the lattice constants a = 572.3 (3) pm, c = 1826.4 (5) pm and ca = 3.191. The new compound CaMn4Al8 crystallizes in the tetragonal system (space group, 14mmm) with the constants a = 895.7 (1) pm, c = 516.8 (1) pm and ca = 0.577. The structure corresponds to a ternary variant of the ThMn12 structure.

Na2Ga3Sb3, eine neue zintlphase mit schichtstruktur

Abstract The new compound Na 2 Ga 3 Sb 3 crystallizes in the orthorhombic system (space group Pnma (No. 62)) with the lattice constants a = 2689.0(8) pm, b = 428.3(2) pm, c = 723.6(3) pm. Ga- and Sb-atoms form in alternative sequence wavelike hexagonal nets. Three of them are connected to threefold sheets, which are stacked in a-direction.

Darstellung und kristallstruktur von Ba2Cd3Bi4

Zusammenfassung Die neue Verbindung Ba2Cd3Bi4 kristallisiert orthorhombisch in der Raumgruppe Cmca mit den Gitterkonstanten a = 703,7(1) pm, b = 1743,8(2) pm und c = 926,7(1) pm. CdBi6-Oktaeder und trigonale CdBi5-Bipyramiden sind uber gemeinsame Ecken und Kanten zu einer Geruststruktur vernetzt. Die Bariumatome sitzen in den Lucken dieses Verbandes und erreichen dabei die Koordinationszahl acht gegenuber den Wismutatomen.

Cs2Si2Te6, ein Polypertelluridosilikat(IV)

Abstract The new compound Cs 2 Si 2 Te 6 crystallizes in the monoclinic system (space group: Cc, No. 9) with the lattice constants a = 828.5(4) pm, b = 1393.5(6) pm, c = 1340.4(6) pm, s = 100.35(12)°. Fivefold Si 2 Te 3 -rings, each formed by two SiTe 4 tetrahedra, connected by common Te atoms and Te-Te groups, are linked by Te bridges to infinite strings.

Cs4GeTe6, ein o-Pertelluridogermanat(IV)

Abstract The new compound Cs 4 GeTe 6 crystallizes in the monoclinic system, space group P2 1 /n (No. 14) with the lattice constants a = 1784.5(8) pm, b = 1398.1(6) pm, c = 786.7(4) pm, β = 101.6(1)°. The Ge-atoms are tetrahedrally coordinated by two single Te-atoms and two “end on” bonded Te 2 -dumbbells, forming hitherto unknown discrete GeTe 6 4− -anions.