Sr₅Ge₂N₆ – A Nitridogermanate with Edge‐sharing Double Tetrahedra

Abstract

The new nitridogermanate Sr5Ge2N6 was obtained as a coarsely crystalline product by Na‐flux technique employing a reaction of Sr, Na, NaN3 and GeO2 in weld shut tantalum‐tubes at temperatures up to 760 °C. The crystal structure was determined by single‐crystal X‐ray methods: (Sr5Ge2N6, space group C2/c (no. 15), a = 1040.8(2), b = 652.08(13), c = 1356.5(3) pm, β = 100.29(3)°, V = 905.8(3)·106 pm3, Z = 4, 1240 observed reflections, 61 parameters, R1 = 0.031). In the solid, there are edge‐sharing [Ge2N6]10− double tetrahedra surrounded by Sr2+ ions. Sr5Ge2N6 was found to be isotypic with Ca5Si2N6.

Ca4Mg5Ge3N10 and Sr2Mg3GaN4.33: Two Mg‐Containing Nitrides and Their Structural Relation to (Sr,Ba)2Si5N8

“…In Ca 4 Mg 5 Ge 3 N 10 , there are two crystallographic tetrahedral positions. The (Mg/Ge)–N distances vary between 1.954(2) and 2.115(8) Å and are in good agreement with the (Mg/Ge)–N bond lengths found in Ca 2 Mg 5 GeN 6 and Sr[Mg 3 GeN 4 ] [1.99 to 2.11 Å] as well as to averaged Mg–N and Ge–N bond lengths known from other ternary or quaternary nitrides , , . (Mg1/Ge1)N 4 tetrahedra are linked through common corners to adjacent tetrahedra.…”

“…Ga2-N4 2.048 (8) known from other ternary or quaternary nitrides. [18][19][20]27,28,[32][33][34][35] (Mg1/Ge1)N 4 tetrahedra are linked through common corners to adjacent tetrahedra. In contrast, (Mg2/Ge2)N 4 units are connected through common corners and edges, whereby edgesharing can solely be observed between (Mg2/Ge2)N 4 tetrahedra.…”

Diversity of Strontium Nitridogermanates(IV): Novel Sr4[GeN4], Sr8Ge2[GeN4], and Sr17Ge2[GeN3]2[GeN4]2

“…Sr 4 [GeN 4 ] was obtained as plate‐shaped, deep red, almost black single crystals with dimensions of about 1 mm. The color is peculiar, as one would expect transparency and a lighter color from comparison with similar compounds, such as Ca 4 [GeN 4 ] (orange), Sr 5 [Ge 2 N 6 ] (yellow), or Sr 7 [GeN 4 ]N 2 (light red) . The darker color of Sr 4 [GeN 4 ] does not seem to arise from surface impurities, as the fragments of crushed crystals are not noticeably lighter.…”

Opposite Modulation of Cell Migration by Distinct Subregions of Urokinase Connecting Peptide

“…This results in different dimensionalities, ranging from 0D anion structures up to 3D networks. Ca 4 GeN 4 ,22 Sr 5 Ge 2 N 6 ,23 and Ba 9 Ge 3 N 10 25 are examples containing less condensed building units of either [GeN 4 ] 8– tetrahedra, [Ge 2 N 6 ] 10– double‐tetrahedra or trigonal planar [GeN 3 ] 5– units. Examples of 1D condensed nitridomagnesogermanates are isostructural Sr 3 GeMgN 4 26 and Ba 3 GeMgN 4 27 with infinite chains of edge‐sharing alternating GeN 4 and MgN 4 tetrahedra as well as Ca 5 Ge 2 N 6 22.…”