English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Br5Nb, triclinic, P1 (no. 2), a = 6.461(1) Å, b = 7.031(1) Å, c = 9.584(2) Å, 2 = 108.84(2)°, 3 = 90.89(2)°, # = 116.16(2)°, V = 363.4 Å, Z = 2, Rgt(F) = 0.036, wRref(F) = 0.086, T = 215 K. Source of material 71 mg NbBr5 (0.144 mmol) and 19 mg (0.358 mmol) Li2CN2 were ground in an agatemortar and filled into a silica ampule.The ampulewas sealed under vacuum, then heated up to 643K, kept at this temperature for 4 days and was afterwards cooled down to room temperature during 8 h. Black, block-shaped crystals were obtained alongwith a black powder, containingLiBr,Li2CN2 and an unknown compound according to X-ray powder diffraction measurements. The black crystals were characterized by single crystal diffraction at 215 K, showing a triclinic, yet unknown modification ofNbBr5.All handling was done in a glove box under argon due to the sensitivity of the materials against air and moisture. Discussion Two orthorhombic crystal structures were already reported for NbBr5:2-NbBr5, crystallizing in the space groupPbma [1] and 3NbBr5 (space groupCcmm) which is showing a one-dimensional stacking disorder [2].Crystals of 2-NbBr5 and 3-NbBr5were obtained at 973 K and 498 K, respectively. Both structures can be described as a hexagonal close packing of Br atoms in which one fifth of the octahedral voids are occupied by Nb. The triclinic, ordered polymorph of NbBr5 also consists of a slightly distorted hexagonal closest packing ofBr atoms. TheNb atoms are situated in 2/5 of the octahedral voids of every second layer, forming dimeric Nb2Br10 units. In 2and 3-NbBr5, the Nb2Br10 molecules are stacked perpendicular to the hexagonal layers of bromine atoms,whereas in the triclinicmodification, the stacking direction of theNb2Br10 dimers runs along [100] which is parallel to the hexagonal layers. The intramolecular bond lengths are in good agreement with the atomic distances reported for the 2and 3-modification: due to the repulsion between the Nb ions, they are not located in the centers of the octahedral voids (d(Nb1—Nb1*) = 4.174(2)Å). Therefore, the bridgingNb1—Br1 bonds (2.712(2) Å and 2.716(1) Å) are significantly longer than the other Nb—Br bonds (2.439(1) Å and 2.456 Å for the axial bonds, 2.405(2) Å and 2.406(1) Å for the equatorial bonds). Z. Kristallogr. NCS 222 (2007) 161-162 / DOI 10.1524/ncrs.2007.0066 161 © by OldenbourgWissenschaftsverlag,München Crystal: black block, size 0.12 × 0.26 × 0.40 mm Wavelength: Mo K2 radiation (0.71073 Å) &: 290.22 cm−1 Diffractometer, scan mode: Stoe IPDS I, $ 2'max: 51.72° N(hkl)measured, N(hkl)unique: 4301, 1310 Criterion for Iobs, N(hkl)gt: Iobs > 2 ((Iobs), 1078 N(param)refined: 55 Programs: SHELXS-97 [3], SHELXS-97 [4], DIAMOND [5] Table 1. Data collection and handling.

Crystal structure of niobium pentabromide, NbBr 5 , a triclinic phase