Low-Dimensional Nitridosilicates Grown from Ca/Li Flux: Void Metal Ca₈In₂SiN₄ and Semiconductor Ca₃SiN₃H

Abstract

Reactions of indium and silicon with lithium nitride in Ca/Li flux produce two new nitridosilicates: CaInSiN (orthorhombic, Ibam; a = 12.904(1) Å, b = 9.688(1) Å, c = 10.899(1) Å, Z = 4) and CaSiNH (monoclinic, C2/c; a = 5.236(1) Å, b = 10.461(3) Å, c = 16.389(4) Å, β = 91.182(4)°, Z = 8). CaInSiN features isolated [SiN] units and indium dimers surrounded by calcium atoms. CaSiNH features infinite chains of corner-sharing SiN tetrahedra and distorted edge-sharing H@Ca octahedra. Optical properties and band structure calculations indicate that CaInSiN is a void metal with calcium and indium states at the Fermi level and CaSiNH is a semiconductor with a band gap of 3.1 eV.

Ba3CrN3H: A New Nitride-Hydride with Trigonal Planar Cr4+

“…Two Cr atoms link up and are present as Cr 4+ and Cr 3+ , as corroborated by susceptibility measurements . In another system described recently, Ca 3 SiN 3 H, SiN 4 tetrahedra link up via corners to form linear chains, while the hydrogen anion is again coordinated by six calcium ions . The hydrogen affinity of alkaline earth metals, in these cases calcium that is abundant in these structures, serves to provide an environment for structurally isolating hydrogen from other metals.…”

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.…”

“…[6] Surprisingly few nitridosilicates contain mutually isolated SiN 4 tetrahedra. They include Ca 4 [SiN 4 ], [4] Ca 8 In 2 [SiN 4 ] [7] and a group of compounds described by the formula M(Mg 3 SiN 4 ) (M=Ca, Sr, Eu), [8] To the best of our knowledge, this makes it the first compound containing silicon in both its highest and lowest oxidation states of + 4 and À 4. 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.…”

“…Surprisingly few nitridosilicates contain mutually isolated SiN 4 tetrahedra. They include Ca 4 [SiN 4 ], [4] Ca 8 In 2 [SiN 4 ] [7] and a group of compounds described by the formula M (Mg 3 SiN 4 ) ( M =Ca, Sr, Eu), [8] in which SiN 4 tetrahedra occur as part of a network consisting mostly of MgN 4 tetrahedra. Here we present two new nitridosilicates; Ca 4 (AlSiN 5 ) and Ca 12 Si 4 [SiN 4 ].…”

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

“…[5,6] In contrast to nitridogermanates, they have a strong tendency towards condensed networks of SiN 4 tetrahedra. These tetrahedra are rarely found separated from each other, with Ca 4 [SiN 4 ], [7] Ca 8 In 2 [SiN 4 ] [8] and arguably M(Mg 3 SiN 4 ) (M = Ca, Sr, Eu) [9] being the exceptions among a plethora of condensed nitridosilicates. [6] To the best of our knowledge, neither [Si II N 2 ] 4nor [Si IV N 3 ] 5units have been reported so far.…”