Hisanori Yamane

Preparation and crystal structure of a new barium silicon nitride, Ba5Si2N6

Abstract Single crystals of a new ternary nitride, Ba5Si2N6, were synthesized by slow cooling from 750°C using a starting mixture of Ba, Si, Na and NaN3, where Na and NaN3 were a flux and a nitrogen source respectively. It crystallizes with orthorhombic symmetry: space group P2 1 2 1 2 1 ( No. 19), a = 6.159, b = 10.305, c = 15.292 A , and Z = 4 . The crystal structure was determined from single-crystal data and refined to R1 = 0.0495 for all 1637 observed reflections and 89 variables. A pair of SiN4 tetrahedra contained in the structure forms a nitridometallate anion of [Si2N6]10 by edge sharing.

Synthesis and crystal structure of Sr2ZnN2 and Ba2ZnN2

Abstract Ternary nitrides, Sr 2 ZnN 2 and Ba 2 ZnN 2 , were prepared from Sr or Ba along with Zn metal using Na metal and NaN 3 as a flux and nitrogen source, respectively. The single crystals were obtained by slow cooling from 750°C. Since these compounds hydrolyze in moist air, the crystals were isolated by washing away excess Na with liquid NH 3 in an inert environment. The structures were determined by single crystal X-ray diffraction: tetragonal, space group I 4/ mmm with Z = 2, a = 3.8568(2), c = 12.935(1) A, and R 1 = 0.049 for Sr 2 ZnN 2 , and a = 4.152(1), c = 13.055(3) A, and R 1 = 0.039 for Ba 2 ZnN 2 . Sr 2 ZnN 2 and Ba 2 ZnN 2 are isostructural with Ca 2 ZnN 2 (Na 2 HgO 2 type) and contain linear [NZnN] 4− nitridometallate anions.

A barium germanium nitride, Ba3Ge2N2, containingx1|Ge2− and GeN24− anions

Abstract Single crystals of a ternary nitride, Ba 3 Ge 2 N 2 , were synthesized by the reaction of Ba and Ge with N form NaN 1 in a Na melt by slow cooling from 750 C. The structure as determined by single crystal X-ray diffraction is monoclinic space group P2 1 /m with Z = 2, and has lattice parameters a = 9.61196(6), b = 4.0466(2), c = 10.1337A β = 113.553(41). The structure consiss of angular nitrodometallate anions of |GeN 2 | and prisos of |Ba 1 Ge] 1 condensed in one dimensions to firm zigzag Zintl anions x 1 |Ge 2− . The Ge N bond length in the |GeN 2 ] 1 anions (L88 A) is similar to those found in the linear MN 2 2 anions, while the Ge Ge bond in the Ge 2 chains (2.50A) is only slightly larger than in elemental Ge (2.45A).

SYNTHESIS AND CRYSTAL STRUCTURE OF A NEW OXYNITRIDE, BA3ZNN2O

Abstract A new oxynitride, Ba3ZnN2O, was prepared as single crystals by slow cooling from 750°C using a starting mixture of Ba, ZnO, NaN3 and Na. The NaN3 and Na were respectively the nitrogen source and flux for the crystal growth. The structure was determined by single crystal X-ray diffraction and is tetragonal, space group P4/mmm with Z = 1, a = 4.088(1), c = 9.272(2)A, and R1 = 0.0288. The structure is composed of {Ba2ZnN2} units and {BaO} layers. The zinc atom is linearly coordinated by two nitrogen atoms to form a nitridometallate anion, [N=Zn=N]4−, as in Ba2ZnN2.