Molecular dynamic simulation of the molecular characteristic and mechanical property of methane hydrate/ water/ ice mixture

The microscopic molecular characteristic will impact on the mechanical property of hydrate. Thus, molecular dynamics simulation is employed to investigate the molecular characteristic and mechanical property of methane hydrate/ water/ ice mixture system. The brittle fracture occurred during the tensile deformation of the system. Besides, the maximum stress of the hydrate/ water/ ice mixture system is lower than that of intact hydrate system. The fracture strain of studied system is smaller than that of pure hydrate system. The order parameters F3 and F4 can be used for determining the fracture position of mixture system and the changing of micro configuration on the mixture interface.

Synthesis and crystal structure of anhydrous Na[MnO4]

There are numerous reports in the literature about the amount of hydrate water in sodium permanganate, which is said to be between one half and three water molecules per Na[MnO4]. Because no structural descriptions of the hydrate and the anhydrous compound can be found yet, this work reports the synthesis of anhydrous Na[MnO4] via the Muthmann method and its crystal structure. Na[MnO4] crystallizes as dark purple needles in the monoclinic space group P21/n with a = 572.98(5), b = 842.59(7), c = 715.47(6) pm, β = 92.374(3)° and Z = 4. As such and with its isotype to Ag[MnO4], Na[MnO4] completes the series of anhydrous alkali-metal permanganates, comprising Li[MnO4] (orthorhombic, Cmcm, Cr[VO4] type) and the isostructural heavier congeners A[MnO4] (A = K, Rb, Cs; orthorhombic, Pnma, Ba[SO4] type).