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

Abstract

Single crystals of three new strontium nitridogermanates(IV) were grown in sealed niobium ampules from sodium flux. Dark red Sr4[GeN4] crystallizes in space group P21/c with a = 9.7923(2) Å, b = 6.3990(1) Å, c = 11.6924(3) Å and β = 115.966(1)°. Black Sr8Ge2[GeN4] contains Ge4– anions coexisting with [GeIVN4]8– tetrahedra and adopts space group Cc with a = 10.1117(4) Å, b = 17.1073(7) Å, c = 10.0473(4) Å and β = 115.966(1)°. Black Sr17Ge6N14 features the same anions alongside trigonal planar [GeIVN3]5– units. It crystallizes in P1 with a = 7.5392(1) Å, b = 9.7502(2) Å, c = 11.6761(2) Å, α = 103.308(1)°, β = 94.651(1)° and γ = 110.248(1)°.

Diversity in Nitridosilicate Chemistry: The Nitridoalumosilicate Ca4(AlSiN5) and the Nitridosilicate Silicide Ca12Si4[SiN4]

“…CaÀ N and especially CaÀ Si 4À distances vary significantly, as can be taken from Table 2. The [SiN 4 ] 8tetrahedron acts as a monodentate ligand for Ca(4), Ca(5), Ca (11) and Ca (12), a bidentate ligand for Ca(1), Ca(3), Ca(6), Ca (7), Ca (9) and Ca (10) and a tridentate ligand for Ca (8). Each individual nitrogen atom is coordinated by an octahedron of one silicon and five calcium atoms, except for N(2), around which a trigonal bipyramid is formed instead.…”

“…In this regard, it is similar to the nitridogermanate germanides Sr 8 Ge 2 [GeN 4 ] and Sr 17 Ge 2 [GeN 3 ] 2 [GeN 4 ] 2 reported recently. [9] Though highly unusual, silicide Zintl ions coexisting with silicate ions are not entirely unprecedented in oxide chemistry either: Cs 10 [Si 4 ][Si 3 O 9 ] and Rb 14 [Si 4 ][Si 6 O 17 ], [10] two oxosilicate silicides with tetrahedral [Si 4 ] 4À anions, as well as several similar germanates and stannates have been studied by Caroline Röhr two decades ago. [11]…”

Li16Sr6Ge6N, Li16Sr6Ge6.5 and related lithium alkaline‐earth metal tetrelides: Alternative filling of voids by nitride or tetrelide ions

“…Silicon in nitridosilicates(IV) is always coordinated tetrahedrally by nitrogen like in the famous Sr 2 Si 5 N 8 . [1][2] However, nitridogermanate(IV) ions generally feature Ge in tetrahedral [Ge IV N 4/x ] yÀ (e. g. Sr 4 [GeN 4 ], Li 4 Sr 3 [Ge 2 N 6 ]) [3,4] or trigonal planar [Ge IV N 3 ] 5À (e. g. Sr 17 [Ge] 2 [GeN 3 ] 2 [GeN 4 ] 2 ) [3] coordination by nitrogen forming complex networks of different dimensionalities. In nitridogermanates(III), additional direct GeÀ Ge inter-actions are observed in Sr 6 [Ge 2 N 6 ] with Ge in a tetrahedral coordination by one further Ge and three N atoms.…”

“…[5] Two-fold, bent [Ge II N 2 ] 4À coordination is observed in nitridogermanates(II) (e. g. Sr 2 [GeN 2 ]); [6] some of these phases may be classified as nitridogermanate-germanides containing also metalide anions. [3] For tin, with NaSnN only one example of a nitridostannate(II) is known, [7] while lead rather forms plumbides.…”

“…In nitridogermanates(III), additional direct Ge−Ge interactions are observed in Sr 6 [Ge 2 N 6 ] with Ge in a tetrahedral coordination by one further Ge and three N atoms [5] . Two‐fold, bent [Ge II N 2 ] 4− coordination is observed in nitridogermanates(II) (e. g. Sr 2 [GeN 2 ]); [6] some of these phases may be classified as nitridogermanate‐germanides containing also metalide anions [3] . For tin, with NaSnN only one example of a nitridostannate(II) is known, [7] while lead rather forms plumbides.…”