Z. Kristallogr. NCS 219 (2004) 349-350 349 © by Oldenbourg Wissenschaftsverlag, München Crystal structure of hexabarium mononitride pentaindide, (Ba6N)[In5] A. Schlechte, Yu. Prots and R. Niewa* Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Str. 40, 01187 Dresden, Germany Received October 1, 2004, accepted and available on-line November 12, 2004; CSD no. 409805 Discussion Indium, when combined with alkaline-earth elements forms a va- riety of ternary nitrides. The compounds known so far may be de- scribed as built from indium clusters and octahedra of alkaline- earth cations surrounding nitride ions. In the latter cationic sub- structure the polyhedra might be isolated, vertex-, and/or edge- sharing. The variety of In arrangements extends from isolated In species in (Ca7N4)Ini.o4 [1], isolated tetrahedral units in (AI9N7)[ID4]2 (A = Ca, Sr, Ba) [2,3], trigonal bipyramidal [Ins] clusters next to [Ins] ions of more complicated geometry in (Ba38Ni8)[In5]2[In8] [4], and infinite chains in (A4N)[In2] (A = Ca, Sr) [5] and (Ca2N)In [6]. None of these metallic compounds follows Zintl-like counting. The new compound (Ba6N)[Ins] is an isotype of (¿6N)[Ga5] (A = Sr, Ba) [7]. The crystal structure of (Ba6N)tIns] is characterized as rocksalt type motif of N-centred octahedra (BaiN) and trigonal bi- pyramidal clusters [Ins]. The trigonal bipyramidal units [Ins] might be described as [Ins]7- ions, quite the same according to Zintl-type electronic counting and using the Wade-rules for closo-cluster. The isotypes (AeN)[Gas] were previously de- scribed by the formula (A2+)6(N3-)[Ga5]7~ • 2e_ based on elec- tronic structure calculations. An alternate speculation on unnoticed hydride ion impurities in the sense of '(A6N)[£s]H2' (E = Ga, In) is falsificated for the title compound by chemical analyses on hydrogen on a nearly single phase sample: The hydrogen content is below the detection limit of 160 ppm C(Ba6N)[In5]H2': 1400 ppm), w(O) = 0.10(3) wt.%. For the [Ins] cluster in (Ba38Ni8)[In5]2[In8] a highly electron deficient situa- tion ([Ins]^ was derived [4]. Distances within the [Ins] unit in Abstract _ (BaeNXIns] with ¿(In—In)eqUatoriai = 3.061(1) A and ¿(In—fac- BaelnsN, trigonal, R3c (no. 167), a = 8.234(3) A, ial = 3.057(1) A are in the range of the respective distances in 3 c = 44.12(2) A, V = 2590.6 A , Z = 6, Rgi(F) = 0.028, (Ba38Ni8)[In5]2[In8] with ¿(In—InWtoriai = 3.115(1) A, wRreftF2) = 0.060, T= 293 K. 3.164(1) A and ¿(In—InWai = 2.955(1) A - 3.224(2) A. The dis- tances in the isolated (Ba6N) octahedra with ¿(Ba—N) = Source of material 2.7827(8) A are similar to those in (Ba6N)[Ga5] (¿(Ba—N) = Single crystals of (Ba6N)[Ins] with metallic lustre were obtained 2.734(1) A). from reaction of melt beads of the general composition 'Ba3ln' with nitrogen atmosphere at 973 K next to further ternary phases. Table 1. Data collection and handling. Nearly single phase material (according to X-ray powder diffrac- tion) was obtained under the same conditions starting from melt Crystal: gray platelet, beads with the bulk composition 'Ba6lns' after two reannealing size 0.035 x 0.110 x 0.110 mm cycles at 973 K. Wavelength: Mo Ka radiation (0.71073 A) 1 P- 199.35 cm" Diffractometer, scan mode: Experimental details Rigaku AFC 7 & Mercury CCD, X = O°,<o = O°,20 = -10°, <p = 0° - 180°, Chemical analyses on impurities of H and O were carried out A<p = 0.5°, t = 6 sec using the carrier gas hot-extraction technique on a LECO ana- X = -90°, <p = 25°, 2B = -10°, m = 0° - 60°, lyzer TCH-600. Lattice parameters were obtained from least- Atu = 0.5°, r = 6 sec squares fittings of reflections taken from a Guinier powder pattern 'l&nax' 67.1° (Cu Ka\ radiation, A = 1.540598 A). N(hkl)ma&\xaA, Nfhkl)^^: 8837,1079 Criterion for /obs, N(hU)gc. /obs > 2 (TfW, 1021 N(param)nBxA' 20 Programs: SHELXS-97 [8], SHELXL-97 [9] * Correspondence author (e-mail: [email protected]) 350 (BaeNHIns] Table 2. Atomic coordinates and displacement parameters (in Â2). Atom Site U il U22 t/33 V12 U13 1/23 Ba(l) 36c 0.10028(4) 0.31724(4) 0.035077(6) 0.0171(1) 0.0199(1) 0.0195(1) 0.0095(1) -0.00062(8) -0.00081(9) In(l) 18e 0.21465(5) 0 '/4 0.0162(1) 0.0248(2) 0.0192(2) ViU12 -0.00083(8) 21/13 In(2) 12c 0 0 0.19348(1) 0.0213(2) Un 0.0153(2) ViUu 0 0 N(l) 6b 0 0 0 0.023(3) V11 0.025(5) ViUu 0 0 Acknowledgments. We thank Ulrike Schmidt for performing the chemical analyses and Prof. Dr. Rüdiger Kniep for fruitful discussions. References 1. Höhn, P.; Ramlau, R.; Rosner, H.; Schnelle, W.; Kniep, R.: (Ca7N4)Mx 5. Cordier, G.; Rônninger, S.: Darstellung und Kristallstruktur von Ca4n2N (M = Ag, Ga, In, Tl): Subnitride und Metallketten ¿Ai,. Z. Anorg. Allg. und Sr4n2N. Z. Naturforsch. 42b (1987) 825-827. Chem. 630 (2004) 1704. 6. Bailey, M. S.; DiSalvo, F. J.: The synthesis and structure of Ca2lnN, a 2. Cordier, G.; Rönninger, S.: Zur Stnikturchemie von Erdalkali-Nitrido- novel ternary indium nitride. J. Alloys Compd. 353 (2003) 146-152. Gallaten und -Indaten. Z. Kristallogr. Suppl. 182 (1988) 60-61. 7. Cordier, G.; Ludwig, M.; Stahl, D.; Schmidt, P. C.; Kniep, R.: (Sr6N)[Gas] 3. Kirchner, M.; Wagner, F. R.; Schnelle, W.; Niewa, R.: Beiträge zur and (Ba«N)[Gaj]: Compounds with Discrete (AfôN) Octahedra and [Gas] Veibindungsbildung im System Ca-In-N. Z. Anorg. Allg. Chem. 630 Qusters. Angew. Chem. Int. Ed. 34 (1995) 1761-1763. (2004) 1735. 8. Sheldrick, G. M.: SHELXS-97. Program for the Solution of Crystal Struc- 4. Yamane, H.; Sasaki, S.; Kajiwara, T.; Yamada, T.; Shimada, M.: tures. University of Gottingen, Germany 1997. Bai9ln9N9, a subnitride containing isolated [Ins]5- and [Ing]12- Zintl an- 9. Sheldrick, G. M.: SHELXL-97. Program for the Refinement of Crystal ions. Acta Crystallogr. E60 (2004) il20-il23. Structures. University of Gottingen, Germany 1997. .