The Indium Subnitrides Ae₆In₄(In_xLi_y)N_3-z (Ae = Sr and Ba)

Abstract

The indium nitrides Sr6In4(In(0.32)Li(0.92))N(2.49) and Ba6In(4.78)N(2.72) have been synthesized from an excess of molten sodium. They crystallize in a stuffed variant of the eta-carbide structure type in the cubic space group Fdm with Z = 8. The lattice parameters are a = 14.3752(4) and 15.216(1) A, with cell volumes 2970.6(2) and 3523.3(6) A3, respectively. In both compounds there are vacancies on some of the indium and nitrogen sites and, in the case of Sr6In4(In(0.32)Li(0.92))N(2.49), mixed lithium-indium occupancy of one metal site. It is demonstrated that the partial and mixed occupancies act to carefully tune to electron count to almost fulfill the bonding requirements of the stellar quadrangular subnets of both compounds. Four probe resistivity measurements performed upon a pellet of Sr6In4(In(0.32)Li(0.92))N(2.49) show it to have a room-temperature resistivity of 6.3 mOmega.cm with a weak temperature dependence.

Synthesis, Characterization, and Chemical Bonding Analysis of the Lithium Alkaline‐earth Metal Gallide Nitrides Li2(Ca3N)2[Ga4] and Li2(Sr3N)2[Ga4]

“…Crystallographic data, atomic coordinates, and isotropic thermal displacement parameters from structure refinements obtained from single‐crystal X‐ray diffraction data are summarized in Table and Table , relevant distances are listed in Table . In contrast to isotypic (Li x In y ) 2 ( ae 3 N 1– x ) 2 [In 4 ] ( ae = Sr, Ba),, neither mutual substitution of Li and Ga nor partial occupation of any site are observed. Refinements of the occupation parameters of all positions resulted in no significant deviations from unity in all cases.…”

“…. [18] Isolated tetrahedra [E 4 ] (E = Ga, In) are observed in Li 7 (Ba 6 N)[Ga 4 ] 2 , [17] the isotypic phases (Ca 19 [20] as well as in the isotypic phases (Li x ,In y ) 2 (AE 3 N 1-x ) 2 [In 4 ] (AE = Sr, [21] Ba [21,22] ); up to now, these latter phases are the only group 13 metalide nitrides sporting a phase width. The isotypic phases (Sr 6 N) [Ga 5 ], [23] (Ba 6 N) [Ga 5 ], [23] .…”

“…Isolated species are observed in the anti‐perovskite (Ca 3 N)[Tl], together with [Ga 4 ] tetrahedra in Li 22 (Ba 12 N 9 )[Ga 4 ] 4 [Ga], or together with zigzag chains in (Ca 7 N 2 )[Tl][Tl 2 ] . Isolated tetrahedra [ E 4 ] ( E = Ga, In) are observed in Li 7 (Ba 6 N)[Ga 4 ] 2 , the isotypic phases (Ca 19 N 7 )[In 4 ] 2 , and (Sr 19 N 7 )[In 4 ] 2 , as well as in the isotypic phases (Li x ,In y ) 2 ( ae 3 N 1– x ) 2 [In 4 ] ( ae = Sr, Ba, ); up to now, these latter phases are the only group 13 metalide nitrides sporting a phase width. The isotypic phases (Sr 6 N)[Ga 5 ], (Ba 6 N)[Ga 5 ], and (Ba 6 N)[In 5 ] contain [ E 5 ] units in the form of trigonal bipyramids.…”

The Crystal Structure of Manganotychite, Na6Mn2(CO3)4(SO4), and Structural Relations in the Northupite Group

“…This allows the consideration of the respective [Cl2Na6] framework in northupite as an antipyrochlo or an inverse pyrochlore, by analogy with antiperovskites or inverse perovskites [31]. Si ilar antipyrochlore frameworks formed by N-centered metal octahedra are known in kaline earth metal nitrides [32,33] and by O-centered (OTi6) octahedra in Ti2[Ti3O]2(P [34].…”

Alkaline‐earth Metal Nitrides of the Main‐Group Elements: Crystal Structures and Properties of Inverse Perovskites

“…On increasing the In or Tl content in the composition related phases with E-E covalent bonding, nitrogen exclusively sur- 8 ] ions of more complicated shape (2-fold edge-capped octahedron), [62] to infinite chains contained in, e.g., (Ca 7 N 4 )E x (E = In, Tl, x close to 1), [63] (Ca 2 N)In, [64] and [66] A close similarity in structural chemistry and chemical bonding properties of these compounds to isostructural compounds containing anionic silver or gold next to nitride ions is indicated with the existence of (Ca 19 N 7 )[Ag 4 ], [67] (Ca 7 N 4 )Ag x (x = 2.72), [68] and (A 2 N)Au. [68,69] Originally the cubic calcium Perovskites with E = Ge, Sn, Pb were reported with the composition (Ca 3 N)E, [18] later the systems Sr,Ba-Sn,Pb-N were exemplarily studied in deeper detail indicating the formation of further cubic Perovskites but with a nitrogen deficiency according to (A 3 N x )E. [20,70] DTA/ TG measurements on melt beads with the general composition "A 3 E" in nitrogen atmosphere already indicated the uptake of less than one equivalent nitrogen per "A 3 Sn,Pb" composition.…”