Download citation
Download citation

link to html
The title compound, Li3AsS4·8H2O, is built up from infinite cationic [Li3(H2O)8]3+ chains which extend along [001] and are cross-linked by isolated tetra­hedral AsS43− anions via O—H...S hydrogen bonds. Two Li and two As atoms lie on special positions with site symmetries -1 (1 × Li) and 2 (1 × Li and 2 × As). The [Li3(H2O)8]3+ chain contains four independent Li atoms of which two are in octa­hedral and two in tetra­hedral coordination by water O atoms. An outstanding feature of this chain is a linear group of three edge-sharing LiO6 octa­hedra to both ends of which two LiO4 tetra­hedra are attached by face-sharing. Such groups of composition Li5O16 are linked into branched chains by means of a further LiO4 tetra­hedron sharing vertices with four adjacent LiO6 octa­hedra. The Li—O bonds range from 1.876 (5) to 2.054 (6) Å for the LiO4 tetra­hedra and from 2.026 (5) to 2.319 (5) Å for the LiO6 octa­hedra. The two independent AsS43− anions have As—S bond lengths ranging from 2.1482 (6) to 2.1677 (6) Å [<As—S> = 2.161 (10) Å]. The eight independent water mol­ecules of the structure donate 16 relatively straight O—H...S hydrogen bonds to all S atoms of the AsS4 tetra­hedra [<O...S> = 3.295 (92) Å]. Seven water mol­ecules are in distorted tetra­hedral coordination by two Li and two S; one water mol­ecule has a flat pyramidal coordination by one Li and two S. At variance with related compounds like Schlippe's salt, Na3SbS4·9H2O, there are neither alkali–sulfur bonds nor O—H...O hydrogen bonds in the structure.

Download citation
Download citation

link to html
The crystal structure of tamarugite [sodium aluminium bis­(sulfate) hexa­hydrate] was redetermined from a single crystal from Mina Alcaparossa, near Cerritos Bayos, southwest of Calama, Chile. In contrast to the previous work [Robinson & Fang (1969). Am. Mineral. 54, 19–30], all non-H atoms were refined with anisotropic displacement parameters and H-atoms were located by difference Fourier methods and refined from X-ray diffraction data. The structure is built up from nearly regular [Al(H2O)6]3+ octa­hedra and infinite double-stranded chains [Na(SO4)2]3− that extend parallel to [001]. The Na+ cation has a strongly distorted octa­hedral coordination by sulfate O atoms [Na—O = 2.2709 (11) – 2.5117 (12) Å], of which five are furnished by the chain-building sulfate group S2O4 and one by the non-bridging sulfate group S1O4. The [Na(SO4)2]3− chain features an unusual centrosymmetric group formed by two NaO6 octa­hedra and two S2O4 tetra­hedra sharing five adjacent edges, one between two NaO6 octa­hedra and two each between the resulting double octa­hedron and two S2O4 tetra­hedra. These groups are then linked into a double-stranded chain via corner-sharing between NaO6 octa­hedra and S2O4 tetra­hedra. The S1O4 group, attached to Na in the terminal position, completes the chains. The [Al(H2O)6]3+ octa­hedron (〈Al—O〉 = 1.885 (11) Å) donates 12 comparatively strong hydrogen bonds (O...O = 2.6665 (14) – 2.7971 (15) Å) to the sulfate O atoms of three neighbouring [Na(SO4)2]3− chains, helping to connect them in three dimensions, but with a prevalence parallel to (010), the cleavage plane of the mineral. Compared with the previous work on tamarugite, the bond precision of Al—O bond lengths as an example improved from 0.024 to 0.001 Å.

Download citation
Download citation

link to html
In the crystal structure of Na2SeO3·5H2O [disodium selen­ate(IV) penta­hydrate], two Se, two selenite O atoms and one water O atom are located on a mirror plane, and one water O atom is located on a twofold rotation axis. The coordination of one Na+ cation is distorted trigonal bipyramidal, formed by three equatorial H2O ligands and two axial selenite O atoms. The other Na+ cation has an octa­hedral coordination by six water mol­ecules. The two independent SeO3 groups form almost undistorted trigonal pyramids, with Se—O bond lengths in the range 1.6856 (7)–1.7202 (10) Å and O—Se—O angles in the range 101.98 (3)–103.11 (5)°, and both are μ2-O:O-bonded to a pair of Na+ cations. Hydrogen bonds involving all water molecules and selenite O atoms consolidate the crystal packing. Although anhydrous Na2SeO3 and Na2TeO3 are isotypic, the title compound is surprisingly not isotypic with Na2TeO3·5H2O. In the tellurite hydrate, all Na+ cations have an octa­hedral coordination and the TeO3 groups are bonded to Na+ only via one of their three O atoms.

Download citation
Download citation

link to html
In the title compound, [Ir(C15H22BN6)(C8H7O)Cl]·CHCl3, the Ir atom is formally trivalent and is coordinated in a slightly distorted octa­hedral geometry by three facial N atoms, one C atom, one O atom and one Cl atom. The Ir=Ccarbene bond is strong and short and exerts a notable effect on the trans-Ir—N bond, which is about 0.10 Å longer than the two other Ir—N bonds. The chloro­form solvent mol­ecule is anchored via a weak C—H...Cl hydrogen bond to the Cl atom of the Ir complex mol­ecule. In the crystal, the constituents adopt a layer-like arrangement parallel to (010) and are held together by weak inter­molecular C—H...Cl hydrogen bonds, as well as weak Cl...Cl [3.498 (2) Å] and Cl...π [3.360 (4) Å] inter­actions. A weak intra­molecular C—H...O hydrogen bond is also observed.

Download citation
Download citation

link to html
In the mononuclear title iridium(III) complex, [Ir(C4H8)(C15H22BN6)(C3H9P)], which is based on the [tris­(3,5-dimethyl­pyrazol-1-yl)hydro­borato]iridium moiety, Ir[TpMe2], the IrIII atom is coordinated by a chelating butane-1,4-diyl fragment and a trimethyl­phosphane ligand in a modestly distorted octa­hedral coordination environment formed by three facial N, two C and one P atom. The iridium–butane-1,4-diyl ring has an envelope conformation. This ring is disordered because alternately the second or the third C atom of the butane-1,4-diyl fragment function as an envelope flap atom (the occupancy ratio is 1:1). In the crystal, mol­ecules are organized into densely packed columns extending along [101]. Coherence between the mol­ecules is essentially based on van der Waals inter­actions.
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds