Mn II Compounds

Most of Mn(II) compounds are high spin. Whether they are octahedral or tetrahedral they have 5 unpaired electrons and hence they have the highest magnetic susceptibility in the transition series. Some salts are used as susceptibility standards. 

Since the ground state configuration is A g in Oh symmetry, any transition to higher states will be spin- and Laporte-forbidden. Hence the d-d electronic spectrum is expected to exhibit weak bands but some of these may be sharp. 

Grind a very pure Mn(II) sulphate or chloride to a very fine size. Pack in the Gouy tube and measure the susceptibility by the Gouy or Evans methods (Sec.2.1.3) and calculate the magnetic moment. 

Prepare a concentrated solution of Mn(II) nitrate and run its spectrum in a 4 cm cell (or a 10 cm cell if available) over the range 300-700 nm. 

Draw your conclusions from your results. 

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Peroxymonosulphuric acid (PMSA, H SO ) proved to be a promising oxidizer in reactions with chemiluminescent substances (luminol) with participation of such ions as Mn(II), Cu(II), Ni(II), Cr(IV), V(V). The literature data show the possibility of utilization PMSA in indicating reaction with ferroin ([Fe(l,10-phenanthrolyne) ] ) which is accelerated by Mn(II) compounds. 

Figure 1. XANES spectra for crystallographically characterized Mn(II), Mn(III), and Mn(IV) model compounds. Long dashed lines indicate Mn(II) compounds solid lines indicate Mn(III) compounds short dashed lines indicate Mn(IV) complexes. The models chosen to illustrate this phenomenon are[Mn(ll)HB(3,5-iPr2pz) 3]2(OH) 2and(pyrazolyl) 2Mn(OCfi3) 3Mn(ll) (HB 3,5-iPr2pz)3 [where HB(3,5-iPr2pz)3 is hydrotris(3,5-diisopropyl-1-pyrazolyl borate) Mn(II)(hexakisimidazole)Cl2 Mn(III)(acac)3 Mn(III)2, [2-OH-(5-Cl-SAL)PN]2(CH3OH), [Mn(IV) (n2-0) (SALPN)]2, and [Mn(IV)-(SALPN)]2(h2-0)(h2-OH) [where SALPN is l,3-bis(salicylideneimanato) propane] [Mn(III) (SALAHP) (AcO)]2 [where SALAHP is 3-(salicylideneim-inato)-2-methyl- 1,3-dihydroxy propane] and Mn(IV) (SALADHP) 2 [where SALADHP is the dianion of 2-methy 1-2-(salicylideneamino)-1,3-dihydroxy-propane].

Manganese(II) oxide is a basic oxide, insoluble in water but dissolving in acids to give pale pink solutions containing [Mn(H20)g]. The oxidation of Mn(II) compounds in acidic solution requires a powerful oxidant such as periodate, but in alkaline media, oxidation is easier because hydrous Mu203 is far less soluble than Mn(OH)2. Thus, when alkali is added to a solution of a Mn(II) salt in the presence of air, the white precipitate of Mn(OH)2 that initially forms rapidly darkens owing to atmospheric oxidation. 

Bacteria that are able to use Fe(II) and Mn(II) compounds as electron donors and derive energy for their growth from oxidation. 

The purple permanganate ion [14333-13-2], MnOu can be obtained from lower valent manganese compounds by a wide variety of reactions, eg, from manganese metal by anodic oxidation from Mn(II) solution by oxidants such as o2one, periodate, bismuthate, and persulfate (using Ag" as catalyst), lead peroxide in acid, or chlorine in base or from MnO by disproportionation, or chemical or electrochemical oxidation. 

Mn(II) > Mg(II).270 It should be underlined that titanium and zirconium alkoxides are efficient catalysts for both stages of reaction. Lanthanide compounds such as 2,2/-bipyridyl, acetylacetonate, and o-formyl phenolate complexes of Eu(III), La(III), Sm(III), Er(III), and Tb(III) appear to be even more efficient than titanium alkoxides, Ca or Mn acetates, Sb203, and their mixtures.273 Moreover, PET produced with lanthanides has been reported to exhibit better thermal and hydrolytic stability as compared to PET synthesized with the conventional Ca acetate -Sb203 catalytic system.273... 

The reports about the crystal structure of Mn(Et2cftc)2, determined by means of X-ray powder diagrams are contradictory. According to Fackler and Holah (18) this compound is isomorphous with Cu(Et2rftc)2, but Lahiry and Anand (44) state the complex to be isostructural with Ni(Et2 tc)2- EPR data (g = 1.92 and g = 4.11) and magnetic susceptibility measurements (4.1 BM at room temperature) show the compound to be the first Mn(II) complex with a quartet ground state (44). 

Baron, V., Gillon, B., Plantevin, O. et al. (1996) Spin-density maps for an oxamido-bridged Mn(II)Cu(II) binuclear compound. Polarized neutron diffraction and theoretical studies, J. Am. Chem. Soc., 118, 11822-11830. 

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