Poly[[di-μ3-nicotinato-μ3-oxalato-samarium(III)silver(I)] dihydrate]

In the title three-dimensional heterometallic complex, {[AgSm(C6H4NO2)2(C2O4)]·2H2O}n, the SmIII ion is eight-coordinated by four O atoms from four different nicotinate ligands and four O atoms from two different oxalate ligands. The three-coordinate AgI ion is bonded to two N atoms from two different nicotinate anions and one O atom from an oxalate anion. These metal coordination units are connected by bridging nicotinate and oxalate ligands, generating a three-dimensional network. The uncoordinated water mol­ecules link the carboxyl­ate groups via O—H⋯O hydrogen bonding. The crystal structure is further stabilized by hydrogen bonds between the water mol­ecules

8-Acetyl-4-methyl-2-oxo-2H-chromen-7-yl acetate

In the title compound, C14H12O5, the benzopyran-2-one ring system is approximately planar [maximum deviation = 0.018 (1) Å]; the mean plane is oriented at dihedral angles of 52.26 (11) and 72.92 (7)°, respectively, to the acetyl and acet­oxy groups. In the crystal, π–π stacking is observed between parallel benzene rings of adjacent mol­ecules, the centroid–centroid distance being 3.6774 (17) Å. Inter­molecular weak C—H⋯O hydrogen bonding, and C=O⋯C=O [O⋯C = 3.058 (3) Å] and C=O⋯π [O⋯centroid = 3.328 (2) Å] inter­actions occur in the crystal structure

Bis(1,3-diethyl­benzimidazolium) tetra­bromidomercurate(II)

In the title compound, (C11H15N2)2[HgBr4], the tetra­coordinated HgII center of the complex anion adopts a distorted tetra­hedral geometry [Hg—Br = 2.5755 (8)–2.623 (11) Å and Br—Hg—Br = 103.78 (19)–116.4 (3)°]. One of the Br atoms is disordered over two sites [site-occupancy factors = 0.51 (6) and 0.49 (6)]. The N—C—N angles in the cations are 110.7 (6) and 111.4 (7)°. In the crystal packing, a supra­molecular chain is formed via both weak inter­molecular C—H⋯Br hydrogen bonds and π–π aromatic ring stacking inter­actions [centroid–centroid separation = 3.803 (1) Å]

Poly[[di-μ3-nicotinato-μ3-oxalato-samarium(III)silver(I)] dihydrate]. Corrigendum

Corrigendum to Acta Cryst. (2009), E65, m1105

Spatial distribution of NH2D in massive star-forming regions

To understand the relation between NH$_2$D and its physical environment, we mapped ortho-NH$_2$D $1_{11}^s-1_{01}^a$ at 85.9 GHz toward 24 Galactic late-stage massive star-forming regions with Institut de Radioastronomie Millim$\'e$trique (IRAM) 30-m telescope. Ortho-NH$_2$D $1_{11}^s-1_{01}^a$ was detected in 18 of 24 sources. Comparing with the distribution of H$^{13}$CN 1-0 as a dense gas tracer and radio recombination line H42$\alpha$, ortho-NH$_2$D $1_{11}^s-1_{01}^a$ present complex and diverse spatial distribution in these targets. 11 of the 18 targets, present a different distribution between ortho-NH$_2$D $1_{11}^s-1_{01}^a$ and H$^{13}$CN 1-0, while no significant difference between these two lines can be found in the other 7 sources, mainly due to limited spatial resolution and sensitivity. Moreover, with H42$\alpha$ tracing massive young stellar objects, ortho-NH$_2$D $1_{11}^s-1_{01}^a$ seems to show a relatively weak emission near the massive young stellar objects.Comment: 30 pages, 20 figures, 4 tables. Accepted to MNRA