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The seismic anisotropy observed in Earth's lowermost mantle (D″ layer) is thought to originate from the lattice‐preferred orientation (LPO) of mantle materials induced by plastic deformation. Ferropericlase is the second most abundant mineral in the lower mantle, and its LPO induced by deformation may significantly contribute to the seismic anisotropy in the D″ layer. The slip system(s) of ferropericlase controlling the LPO in the D″ layer is still controversial, owing to technical difficulties in conducting high‐pressure deformation experiments. We conducted shear deformation experiments on MgO under pressures of up to 120 GPa and reported the LPO after the deformation experiments. Our results indicate that {100}<011> is the dominant slip system in the D″ layer. The LPO developed during shear deformation would result in shear wave splitting with VSH> VSV,consistent with seismic observations in the regions expected to accommodate large shear strain by subducted slabs in the D″ layer. Heat from Earth's core induces active thermal convection involving plastic flow in the Earth's solid mantle. Owing to plastic flow, minerals with elastic anisotropy in the mantle are thought to be aligned in certain directions (lattice‐preferred orientation, LPO) and generate the seismic anisotropy observed in the lowermost mantle. In particular, the LPO of ferropericlase, the second most abundant mineral in the lower mantle, has garnered attention as a likely candidate for attributing the seismic anisotropy of the lowermost mantle. To quantitatively interpret the dynamics of mantle convection in the lowermost mantle from seismic observations, it is essential to understand the LPO patterns of ferropericlase during deformation under the lowermost mantle conditions (for instance, extremely high‐pressure conditions at 1.2 million atmospheric pressure). However, owing to technical difficulties in conducting high‐pressure deformation experiments, there have been uncertainties in the deformation‐induced LPO of ferropericlase in the lowermost mantle. We conducted shear deformation experiments of MgO under the lowermost mantle pressure for the first time and demonstrated that the LPO of MgO produced by shear deformation is indeed consistent with the seismic anisotropy observed in parts of the lowermost mantle expected to accommodate large shear deformation by subducted slabs. Strain rate controlled shear deformation experiments on MgO were conducted under lowermost mantle pressure (120 GPa) for the first timeLarge strain deformation experiments on MgO show that the {100}<011> slip is dominant in the D″ layerA {100}<011> slip of MgO by shear deformation results in VSH> VSVshear splitting, consistent with seismic observations in the D″ layer Strain rate controlled shear deformation experiments on MgO were conducted under lowermost mantle pressure (120 GPa) for the first time Large strain deformation experiments on MgO show that the {100}<011> slip is dominant in the D″ layer A {100}<011> slip of MgO by shear deformation results in VSH> VSVshear splitting, consistent with seismic observations in the D″ layer

Free radical copolymerization reactions of ketene diethylmercaptal (I) and p-methyl-mercaptostyrene (III) with styrene have been carried out. The Q-values for I and III are found to be 2.7 and 3.3 respectively, and these and other related observations are discussed in terms of electron-sharing conjugation involving 3d-orbital of sulfur atom.

The alkaline hydrolysis of substituted phenyl benzenethiolsulfonates has been investigated. The rate was found to be first order with respect to both hydroxide and ester. The second order rate constant for the unsubstituted ester was found to be 3.2×103m−1sec−1(water 45°C). The Hammett ρ values were found to be ρX,Y=H=2.1 and ρY,X=H=1−1 for (Remark: Graphics omitted.) respectively. The reactivities of three esters, i. e. phenyl benzenethiolsulfonate, -thiolsulfonate and -sulfonate were compared.

We developed a thermodynamic model to explore the joint solubility of Mg, Si, and O in liquid Fe on the basis of high‐pressure metal‐silicate partitioning data in the literature, with more Mg kept in the metal when Si and O are present. With <1.7 ±0.5 wt% Mg, the metal in the young Earth's core retains Mg as the core evolves and crystallizes SiO2. Higher Mg concentrations require either the late addition of metal that equilibrated with silicate in a super‐liquidus magma ocean or the assimilation of silicate into the core at the time of a giant impact. Above 1.7 wt% Mg, (Mg,Fe)‐silicate melts also exsolve from the core and transfer core‐hosted elements to the mantle. Fractional crystallization of the core‐derived silicate melts in the core or at the core‐mantle boundary could, additionally, yield a persistent molten silicate layer that could also contribute to ultralow velocity zone formation in the lowermost mantle. Some think that crystallization of oxide in the liquid core, either MgO or SiO2, could have been responsible for driving core convection and geodynamo since early Earth times, at least until iron started crystallizing the inner core. However, the joint solubility of Mg, Si, and O in liquid Fe has not been explored yet. Here we developed a thermodynamic model to examine the exsolution of MgO and SiO2from liquid Fe at core‐mantle boundary (CMB) pressure based on earlier experimental data on metal‐silicate partitioning. Our main findings are that (1) more Mg is retained in the presence of Si and O in metal; (2) with <1.7 wt% Mg, the core expels solid SiO2but not MgO; and (3) with higher Mg, magnesium silicate melt also exolves and transfers core‐hosted elements to the mantle. The seismologically observed molten silicate layer above the CMB may have been originally derived from the core. Mg uptake in liquid iron is controlled by the liquid's Si content; silicate Mg is reduced by Si in the metalIf the core later expelled Mg ingested while accreting as (Mg,Fe)‐silicate, it could transfer siderophile trace elements back to the mantleULVZs at the base of the mantle could be related to fractional crystallization of (Mg,Fe) silicate expelled by the core

Magnesium partitioning between metal and silicate was experimentally investigated between 34 and 138 GPa, 3,500 and 5,450 K using laser‐heated diamond anvil cells. The 22 measurements are combined with previously published data (total of 49 measurements) to model magnesium metal‐silicate partitioning using a thermodynamically consistent framework based on the interaction parameter formalism. The observations support the mechanism of MgO dissolution in the metal, ruling out other mechanisms. The magnesium partition coefficient depends on temperature and metal composition, but not on pressure or silicate composition. The equilibrium concentration and the exsolution rate of MgO in Earth's core can therefore be calculated for any P, T, and composition. Using a core thermal evolution model, the buoyancy flux converts to a magnetic field at Earth's surface, with dipole intensities between 40 and 70 μT prior to inner core growth, consistent with the paleomagnetic record going back to the Archean. We measure the incorporation of magnesium oxide (one of the main components of Earth's mantle) into iron (the main constituent Earth's core), using extremely high pressure and temperature experiments that mimic the conditions of Earth's mantle and core. We find that magnesium oxide dissolution depends on temperature but not on pressure, and on metal (i.e., core) composition but not silicate (i.e., mantle) composition. Our findings support the idea that magnesium oxide dissolved in the core during its formation will precipitate out during subsequent core cooling. The precipitation should stir the entire core to produce a magnetic field in Earth's distant past, at least as intense as the present‐day field. A new thermodynamic model of magnesium metal‐silicate partitioning is proposed, fitting all previously published data along with 22 new experimentsMgO, not Mg, dissolves into iron; partitioning depends on T and metal composition, and is independent of P and silicate compositionMgO exsolution during Earth's core cooling (~10−6K−1) produces a buoyancy flux on the order of 105 kg/s, able to generate a dipolar magnetic field of 40–70 μT