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Mowarin Emmanuel

About the nomenclature: manganate or manganite?

Bruce Gordon  Follow

Let's go down the ladder. $\ce{KMnO4}$ is permanganate, Mn(VII). $\ce{K2MnO4}$ is manganate, Mn(VI). $\ce{K4MnO4}$ is manganite, Mn(IV). $\ce{LaMnO3}$ is called both manganate and manganite, but Mn(III). In a proper world it should be lower than that manganite. They are pedagogically both wrong if it is La(III).

http://dictionary.sensagent.com/potassium%20manganite/en-en/

Manganese oxidation state nomenclature is a real world mess. Drawing nomenclature parallels to Cl(VII) and downward is not valid. Drawing nomenclature parallels to titanium is poor, for Ti(IV) is the highest common oxidation state. $\ce{SrO + TiO2}$ gives $\ce{SrTiO3}$, properly called titanate, for it is Ti(IV) on both sides.

Organic had the same problem. The highest valence carbocation was tricoordinate, hence a carbonium ion. Magic Acid gave $\ce{CH5^+}$. Carbonium ions were renamed carbenium ions to general confusion. Then, $\ce{CH6^{2+}}$. Organic dropped the ball with direction of optical rotation versus geometric left and right. It was flat out stupid designating E ("trans") and Z ("cis") olefins. The designation should have been abstract rather than language-originated.

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Famous Siadah  Follow
Do better: More
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Hari Dotel  Follow
Also, your statement about optical isomerism is confusing, given that the direction of rotatation of plane-polarized light is More
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Glen Reese  Follow
mazepath.com/uncleal/norbors.gifMore
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Glen McMillian  Follow
P3(1)21 quartz and P3(2)21 berlinite are both levorotatory despite being opposite geometric hands, J. Appl. Crystallogr. 19, 108 (1986). CIP notation flips within unchanged geometry (L-(S)-alanine, L-(R)-cysteine). Achiral PhCOCH3 impurity changes resolved PhCH(OH)CH3 optical rotation, J. Org Chem. 38(10), 1870 (1973).More
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Frank DiMeglio  Follow
mazepath.com/uncleal/norone.pngMore
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