Compressibility of the nitridosilicate SrYb[Si4N7] and the oxonitridoaluminosilicates MYb[Si4−xAlxOxN7−x] (x = 2; M = Sr, Ba)

The compressibilities of the nitridosilicate SrYb[Si4N7] and the oxonitridoaluminosilicates MYb[Si4−xAlxOxN7−x] (x = 2; M = Sr, Ba) were investigated by in situ high-pressure X-ray powder diffraction. Pressures up to 42 GPa were generated using the diamond–anvil cell technique. The title compounds are structurally stable to the highest pressure obtained. A fit of a third-order Birch–Murnaghan equation-of-state to the p–V data results in V0 = 302.91 (6) Å3, B0 = 176 (2) GPa and B′ = 4.4 (2) for SrYb[Si4N7]; V0 = 310.4 (1) Å3, B0 = 161 (2) GPa and B′ = 4.6 (2) for SrYb[Si4−xAlxOxN7−x]; and V0 = 317.3 (5) Å3, B0 = 168 (2) GPa and B′ = 4.7 (2) for BaYb[Si4−xAlxOxN7−x]. While the linear compressibilities of the a and c axes of BaYb[Si4−xAlxOxN7−x] are very similar up to 30 GPa, distinct differences were observed for SrYb[Si4N7] and SrYb[Si4−xAlxOxN7−x], with the c axis being the most compressible axis. In all of the investigated compounds the bulk compressibility is dominated by the compression behaviour of the tetrahedral network, while the size of the substituted cation plays a minor role

Crystal structure of barium oxonitridophosphate, Ba3P6O6N8

Ba3N8O6P6, trigonal, P3 (no. 147), a = 7.40227(9) Å, c = 6.3144(1) Å, V = 299.6 Å3, Z = 1, R(I) = 0.008, R(P) = 0.041, T = 297(2) K

Crystal structure of 4,4-dimethyl-2-(trifluoromethyl)-4,5-dihydro-1H-imidazole, C6H9F3N2

C6H9F3N2, monoclinic, P21/n (no. 14), a = 10.6224(9) Å, b = 11.8639(9) Å, c = 13.3139(11) Å, β = 105.903(3)°, V = 1613.6(2) Å3, Z = 8, Rgt(F) = 0.0618, wRref(F2) = 0.1629, T = 102(2) K [1–3]

Investigations of 2-Thiazoline-2-thiol as a Ligand: Synthesis and X-ray Structures of [Mn\u3csub\u3e2\u3c/sub\u3e(CO)\u3csub\u3e7\u3c/sub\u3e(\u3cem\u3eμ\u3c/em\u3e-NS\u3csub\u3e2\u3c/sub\u3eC\u3csub\u3e3\u3c/sub\u3eH\u3csub\u3e4\u3c/sub\u3e)\u3csub\u3e2\u3c/sub\u3e] and [Mn(CO)\u3csub\u3e3\u3c/sub\u3e(PPh\u3csub\u3e3\u3c/sub\u3e)(\u3cem\u3eκ\u3c/em\u3e\u3csup\u3e2\u3c/sup\u3e-NS\u3csub\u3e2\u3c/sub\u3eC\u3csub\u3e3\u3c/sub\u3eH\u3csub\u3e4\u3c/sub\u3e)]

Treatment of Mn2(CO)10 with 2-thiazoline-2-thiol in the presence of Me3NO at room temperature afforded the dimanganese complexes [Mn2(CO)7(μ-NS2C3H4)2] (1) and [Mn2(CO)6(μ-NS2C3H4)2] (2) in 51 and 34% yields, respectively. Compound 1 was quantitatively converted into 2 when reacted with one equiv of Me3NO. Reaction of 1 with triphenylphosphine at room temperature furnished the mononuclear complex [Mn(CO)3(PPh3)(κ 2-NS2C3H4)] (3) in 66% yield. All three new complexes have been characterized by elemental analyzes and spectroscopic data together with single crystal X-ray diffraction studies for 1 and 3. Compound 1 crystallizes in the orthorhombic space group Pbca with a = 12.4147(2), b = 16.2416(3), c = 19.0841(4) Å, β = 90°, Z = 8 and V = 3848.01(12) Å3 and 3 crystallizes in the monoclinic space group P 21/n with a = 10.41730(10), b = 14.7710(2), c = 14.9209(2) Å, β = 91.1760(10)°, Z = 4 and V = 2295.45(5) Å3

A Theoretical and Experimental Study on the Lewis Acid−Base Adducts (P4E3)·(BX3) (E = S, Se; X = Br, I) and (P4Se3)·(NbCl5)

The Lewis acid−base adducts (P4E3)·(BX3) (E = S, Se; X = Br, I) and (P4Se3)·(NbCl5) have been prepared and characterized by Raman, IR, and solid-state 31P MAS NMR spectroscopy. Hybrid density functional calculations (B3LYP) have been carried out for both the apical and the basal (P4E3)·(BX3) (E = S, Se; X = Br, I) adducts. The thermodynamics of all considered species has been discussed. In accordance with solid-state 31P MAS NMR and vibrational data, the X-ray powder diffraction structures of (P4S3)·(BBr3) [monoclinic, space group P21/m (No. 11), a = 8.8854(1) Å, b = 10.6164(2) Å, c = 6.3682(1) Å, β = 108.912(1)°, V = 568.29(2) Å3, Z = 2] and (P4S3)·(BI3) [orthorhombic, space group Pnma (No. 62), a = 12.5039(5) Å, b = 11.3388(5) Å, c = 8.9298(4) Å, V = 1266.09(9) Å3, Z = 4] indicate the formation of an apical P4S3 complex in the reaction of P4S3 with BX3 (X = Br, I). Basal adducts are formed when P4Se3 is used as the donor species. Vibrational assignment for the normal modes of these adducts has been made on the basis of comparison between theoretically obtained and experimentally observed vibrational data

Structure of (22\u3cem\u3eS\u3c/em\u3e)-3\u3cem\u3eβ\u3c/em\u3e-Acetoxy-20-(3-isopropylisoxazolin-5-yl)-4,4,14 \u3cem\u3eα\u3c/em\u3e-trimethylpregn-8(9)-ene

C32H51NO3, Mr = 497·7, orthorhombic, P212121, a = 7·577 (2), b = 10·510 (2), c = 35·399 (7) Å, V = 2819 (1) Å3, Z = 4, Dx = 1·173 g cm-3, λ (Mo Kα) = 0·71073 Å, μ = 0·69 cm-1, F(000) = 1096, T = 153 K, R = 0·0497 for 2235 observed reflections. The compound investigated is found to be a (22S)-epimer

Structure of 2-Methyl-5,6,7-triphenyl-6,7-dihydropyrazolo[2,3-\u3cem\u3ea\u3c/em\u3e]pyrimidine

C25H21N3, Mr = 363.46, monoclinic, P21/n, a = 9.245 (2), b = 23.502 (5), c = 9.340 (2) Å, β= 103.50(3)°, V=1973.3(2) Å3, Z=4, Dx= 1.220 (2) g cm-3, λ (Mo Kα )= 0.71069 Å, μ = 0.068 cm-1, F(000) = 768, T= 292 K, R = 0.091 for 1442 unique observed reflections. The dihydropyrimidine ring adopts a distorted sofa conformation. The aryl substituents on the saturated C atoms have an axial orientation

On the Effect of Radical Character, Substitution and Atom Encapsulation on the Volume of Icosahedral (Car) boranes1

By means of quantum-mechanical calculations, we study the influence of the charge, spin, substituents, and atom encapsulation on the volume of the cages in icosahedral boranes and carboranes B12H12 2–, CB11H12 –, o-C2B10H12, m- C2B10H12, p-C2B10H12 and 1,2-disubstituted o-C2B10H12.Monoradicals derived from hydrogen abstraction in o-C2B10H12, m-C2B10H12, p-C2B10H12 lead to slight cage contractions (|ΔV| < 0.1 Å3 ). On the other hand, 1,2-disubstitution in o-C2B10H12 and their dianions derived from double proton abstraction on the susbtituent, and {Li+, Be2+} atom encapsulation in B12H12 2–, CB11H12–, o-C2B10H12, m-C2B10H12, p-C2B10H12 always leads to a cage expansion, to a larger extent for endohedral compounds (ΔV ≈ 2 Å3 ) as compared to dianions derived from 1,2-disubstituted o-C2B10H12 (ΔV ≈ 1 Å3 ) and 1,2-disubstituted o-C2B10H12 (ΔV < 0.14 Å3 )

The thermal equation of state of FeTiO_3 ilmenite based on in situ X-ray diffraction at high pressures and temperatures

We present in situ measurements of the unit-cell volume of a natural terrestrial ilmenite (Jagersfontein mine, South Africa) and a synthetic reduced ilmenite (FeTiO_3) at simultaneous high pressure and high temperature up to 16 GPa and 1273 K. Unit-cell volumes were determined using energy-dispersive synchrotron X-ray diffraction in a multi-anvil press. Mössbauer analyses show that the synthetic sample contained insignificant amounts of Fe^(3+) both before and after the experiment. Results were fit to Birch-Murnaghan thermal equations of state, which reproduce the experimental data to within 0.5 and 0.7 GPa for the synthetic and natural samples, respectively. At ambient conditions, the unit-cell volume of the natural sample [V_0 = 314.75 ± 0.23 (1 ) Å^3] is significantly smaller than that of the synthetic sample [V_0 = 319.12 ± 0.26 Å^3]. The difference can be attributed to the presence of impurities and Fe^(3+) in the natural sample. The 1 bar isothermal bulk moduli K_(T0) for the reduced ilmenite is slightly larger than for the natural ilmenite (181 ± 7 and 165 ± 6 GPa, respectively), with pressure derivatives K_0' = 3 ± 1. Our results, combined with literature data, suggest that the unit-cell volume of reduced ilmenite is significantly larger than that of oxidized ilmenite, whereas their thermoelastic parameters are similar. Our data provide more appropriate input parameters for thermo-chemical models of lunar interior evolution, in which reduced ilmenite plays a critical role