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Manganese

About: Manganese is a research topic. Over the lifetime, 40648 publications have been published within this topic receiving 622252 citations. The topic is also known as: Mn & element 25.


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Journal ArticleDOI
TL;DR: The role of redox processes in determining the chemistry of iron and manganese is considered systematically in this article, where the role of micro-organisms in the reduction and oxidation of these two important elements is investigated.

751 citations

Journal ArticleDOI
TL;DR: This new type of dodecanuclear crystalline complex was obtained by reaction of Mn 2÷ with MnO 4 in acetic and propionic acids as mentioned in this paper, which has the formula [Mn12(CHaCOO)I6(H20)4OI2 ].2CH 3COOH.
Abstract: This new type of dodecanuclear crystalline complex was obtained by reaction of Mn 2÷ with MnO 4 in acetic and propionic acids. The reddish-black acetate complex has the formula [Mn12(CHaCOO)I6(H20)4OI2 ] .2CH 3COOH.4H20, established by chemical and singlecrystal X-ray diffraction methods. This complex is tetragonal, space group I~,, with a -- 17.319 (9), c = 12.388 (7)/t,, V = 3716 ,/k 3, Z = 2, M r = 2060.3, D c = 1.84, D,,, = 1.83 Mg m -a. The final R and R w were 0.045 and 0.034 for 1172 non-zero reflexions. The crystals are built up of [MnIE(CH3COO)16(H20)4012] molecules, waters of crystallization and disordered acetic acid molecules. In the dodecanuclear molecules, which have 4 ($4) crystallographic symmetry, the Mn atoms are linked by triply bridging oxo O atoms and by carboxylate bridges from acetate anions. The occurrence of a strong Jahn-Teller effect in Mn a+ ions differentiates the Mn 3+ and Mn 4+ ions. The interesting magnetic properties (the magnetic moment increases from 30-9 x 10 -24 J T -1 at 3-3 K to a maximum of 56.5 x 10 -24 J T -~ in the range 17-31 K and then decreases to 33.4 x 10 -24 J T -~ at 280K per Mn atom) may be interpreted in terms of the Mn-Mn distances and superexchange via bridge O atoms.

750 citations

Journal ArticleDOI
TL;DR: Augmentation d'activite avec des substituants attracteurs d'electrons (dichloro ou dinitro)
Abstract: Augmentation d'activite avec des substituants attracteurs d'electrons (dichloro ou dinitro)

746 citations

Journal ArticleDOI
TL;DR: Data indicate that the IRT1 protein is a broad-range metal ion transporter in plants, which mediates uptake of these metals into plant cells under iron deficiency conditions.
Abstract: The molecular basis for the transport of manganese across membranes in plant cells is poorly understood. We have found that IRT1, an Arabidopsis thaliana metal ion transporter, can complement a mutant Saccharomyces cerevisiae strain defective in high-affinity manganese uptake (smf1 delta). The IRT1 protein has previously been identified as an iron transporter. The current studies demonstrated that IRT1, when expressed in yeast, can transport manganese as well. This manganese uptake activity was inhibited by cadmium, iron(II) and zinc, suggesting that IRT1 can transport these metals. The IRT1 cDNA also complements a zinc uptake-deficient yeast mutant strain (zrt1zrt2), and IRT1-dependent zinc transport in yeast cells is inhibited by cadmium, copper, cobalt and iron(III). However, IRT1 did not complement a copper uptake-deficient yeast mutant (ctr1), implying that this transporter is not involved in the uptake of copper in plant cells. The expression of IRT1 is enhanced in A. thaliana plants grown under iron deficiency. Under these conditions, there were increased levels of root-associated manganese, zinc and cobalt, suggesting that, in addition to iron, IRT1 mediates uptake of these metals into plant cells. Taken together, these data indicate that the IRT1 protein is a broad-range metal ion transporter in plants.

741 citations

Journal ArticleDOI
TL;DR: One-dimension manganese dioxides (α- and β-MnO2) were discovered as effective PDS activators among the diverse manganes oxides for selective degradation of organic contaminants in wastewater and provides a novel catalytic system for selective removal of organic contamination in wastewater.
Abstract: Minerals and transitional metal oxides of earth-abundant elements are desirable catalysts for in situ chemical oxidation in environmental remediation. However, catalytic activation of peroxydisulfate (PDS) by manganese oxides was barely investigated. In this study, one-dimension manganese dioxides (α- and β-MnO2) were discovered as effective PDS activators among the diverse manganese oxides for selective degradation of organic contaminants. Compared with other chemical states and crystallographic structures of manganese oxide, β-MnO2 nanorods exhibited the highest phenol degradation rate (0.044 min-1, 180 min) by activating PDS. A comprehensive study was conducted utilizing electron paramagnetic resonance, chemical probes, radical scavengers, and different solvents to identity the reactive oxygen species (ROS). Singlet oxygen (1O2) was unveiled to be the primary ROS, which was generated by direct oxidation or recombination of superoxide ions and radicals from a metastable manganese intermediate at neutral pH. The study dedicates to the first mechanistic study into PDS activation over manganese oxides and provides a novel catalytic system for selective removal of organic contaminants in wastewater.

733 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,770
20223,534
20211,042
20201,284
20191,667
20181,632