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C26H22N2O2, monoclinic, P21/c (no. 14), a = 16.4367(8) Å, b = 12.7804(6) Å, c = 19.5474(8) Å, β = 96.1700(14)°, V = 4082.5(3) Å3, Z = 8, Rgt(F) = 0.0516, wRref(F2) = 0.1195, T = 273(2) K. [ABSTRACT FROM AUTHOR]

The synthesis and crystal structure of oxy-bridged bis(1 H -tetrazol-5-yl)furazan ( 2 ) were reported. The thermal behavior of 2 was investigated by DSC and TG–FTIR–MS coupling technique. The results showed that the thermolysis of 2 included two stages. The rupture of tetrazole ring occurred with the release of N 2 in the first stage. In the second stage, the striping of HCN from schiff base radical followed by the fragmentation of furazan ether moiety, which leading to the formation of N 2 O, NO and polymer. Furthermore, two decomposition pathways of 2 under electron impact condition were proposed, and the fracture of tetrazole ring and ether bond were considered as the initial step of molecule decomposition, respectively. [ABSTRACT FROM AUTHOR]

Highlights: [•] The crystal structure of the new ionic compound DAT·DNBA was determinated and analyzed. [•] The thermal behavior and the decomposition reaction kinetics were investigated by means of DSC and RSFTIR. [•] Some parameters were calculated to evaluate the thermal stability and safety. [ABSTRACT FROM AUTHOR]

The layered niobium oxide H 4 Nb 6 O 17 (HNO) crystal has an open layered structure. The H 2 O 2 molecules can enter rapidly into the interlayers of HNO crystal, and coordinate with Nb within NbO 6 octahedron to form the peroxy bond intercalated HNO crystal (P-HNO). The introduction of peroxy bond causes the positive shift of the CB minimum of HNO crystal from −0.39 eV to 0.42 eV, resulting in its band gap narrowing from 3.49 eV to 2.68 eV and the improvement of visible light absorption. The photocatalytic investigation indicates that such P-HNO crystal has the visible light photocatalytic performance for RhB dye degradation. Moreover, the trapping experiment indicates that h + and Image 2 are the main active species during the visible light photocatalytic degradation of RhB dye. And the study of photocatalytic degradation mechanism shows that there is a synergy between P-HNO crystal and RhB during the photodegradation of RhB. [ABSTRACT FROM AUTHOR]

The remediation efficiency of the solidification/stabilization (s/s) method on soil contaminated with heavy metals may deteriorate when the treated soil is exposed to freezing–thawing (F–T) cycles. In this study, a series of laboratory tests were conducted to investigate the strength and microstructural characteristics of Zn-contaminated soil treated by cement-soda residue under cyclical F–T conditions. Test results showed that the stress–strain curves were able to be characterized by a strain softening model and the failure mode could be classified as brittle failure before subjecting to F–T cycles. After exposure to the F–T cycles, the stress–strain curves gradually began to resemble the hardening model, and the compressive strength decreased significantly. Unconfined compressive strength (UCS) of the specimens obtained the maximum value at Zn2+ concentration of 2000 mg/kg, regardless of their exposure to the F–T cycles; sample Zn0.2 was the most vulnerable. After being subjected to F–T cycles, micro-cracks formed in the specimens. These cracks would be enlarged by the continuous exposure to F–T cycles, which resulted in the reduction of strength. F–T cycles could significantly damage the crystalline structures of cement hydrates; the damage could also contribute to the deterioration of soil structure. Microstructural analysis results showed that the size of the samples' micro-pores decreased due to the migration of pore water during freezing, while the size of larger pores increased due to ice lens formation and expansion. • Freezing‐thawing (F‐T) cycles cause obvious deterioration in the UCS of the S/S treated Zn-contaminated soil. • The visible cracks are occasionally detectable after 6 F‐T cycles. • F‐T cycles significantly damage the crystalline structures of cement hydrates. • F‐T cycles result in the shrinkage of micro-pores and expansion of macro-pores. [ABSTRACT FROM AUTHOR]