NaZr2N2SCl: A flux-stabilized derivative of zirconium(IV) nitride sulfide (Zr2N2S)

The oxidation of zirconium metal with elemental sulfur and sodium azide (Na N3) should give access to zirconium (IV) nitride sulfide, Zr2N2S, which cou ld crystallize isotypically with the trigonal rare-earth(III) oxide sulfide s M2O2S (M = Y, La-Lu). Appropriate molar admixtures of these reactants tog ether with NaCl added as flux were heated for seven days at 850 degreesC in torch-sealed evacuated silica tubes. As main product, however, pale yellow platelets with the composition NaZr2N2SCl (trigonal, R m; a = 363.56(3), c = 2951.2(4) pm; Z = 3) emerged as single crystals. This pseudo-quaternary compound crystallizes isotypically with e.g. LixEr2HyCl2 (x less than or eq ual to1, y less than or equal to2) in a (doubly) stuffed ZrBr-type structur e and contains at least structural domains of the hypothetical Ce2O2S-analo gous Zr2N2S. Zr4+ resides in monocapped. trigonal anti-prismatic sevenfold coordination of the anions (d(Zr-N) = 218 (3x) and 220 pra (1x), d(Zr-S/Cl) = 266 pm, 3x). Closest packed double-layers of Zr4+ with all tetrahedral i nterstices occupied with N3- are sandwiched by layers of isoelectronic S2- and Cl- anions. These anionic six-layer slabs (S/CI-Zr-N-N-Zr-S/Cl) pile up parallel (001) in a cubic closest packed fashion. Charge balance and struc tural consistence occurs between these layers by intercalation of Na+ withi n octahedral voids (d(Na-S/Cl) = 282 pm, 6x) of double-layers of the indist inguishable heavy anions (S2- and Cl-).