Barium manganate

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Barium manganate
BaMnO4.svg
Barite-unit-cell-3D-vdW.png
Identifiers
3D model (JSmol)
ECHA InfoCard 100.029.190 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 232-109-6
PubChem CID
UNII
  • InChI=1S/Ba.Mn.4O/q+2;;;;2*-1
    Key: ZZCNKSMCIZCVDR-UHFFFAOYSA-N
  • [O-][Mn](=O)(=O)[O-].[Ba+2]
Properties
BaMnO4
Molar mass 256.26 g/mol
Appearancelight blue to dark blue and black powder
Density 4.85 g/cm3
insoluble [1]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
GHS03, GHS07: oxidizing, skin and eye irritant
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Barium manganate is an inorganic compound with the formula BaMnO4. It is used as an oxidant in organic chemistry. [2] It belongs to a class of compounds known as manganates in which the manganese resides in a +6 oxidation state. Manganate should not be confused with permanganate which contains manganese(VII). Barium manganate is a powerful oxidant, popular in organic synthesis and can be used in a wide variety of oxidation reactions.

Contents

Properties

The manganate(VI) ion is a d1 ion and is tetrahedral with bond angles of approximately 109.5°. The Mn−O bond lengths in BaMnO4 and K2MnO4 are identical at 1.66 Å. In comparison, the Mn-O bond length in MnO2−4 is longer than in MnO4 of 1.56 Å and shorter than the Mn−O bond found in MnO2, 1.89 Å. [3] [4] Barium manganate is isomorphous with BaCrO4 and BaSO4. Barium manganate can appear as a dark blue or green to black crystals. [5] Barium manganate is indefinitely stable, active and can be stored for months in dry conditions. [5]

Preparation

Barium manganate can be prepared from potassium manganate and barium chloride by salt metathesis to give insoluble barium manganate: [6]

BaCl2 + K2MnO4 → 2 KCl + BaMnO4

Uses in organic synthesis

Barium manganate oxidizes a number of functional groups efficiently and selectively: alcohols to carbonyls, diols to lactones, thiols to disulfides, aromatic amines to azo-compounds, hydroquinone to p-benzoquinone, benzylamine to benzaldehyde, hydrazones to diazo compounds,

etc. [7] It does not oxidize saturated hydrocarbons, alkenes, unsaturated ketones, and tertiary amines. Barium manganate is a common substitute for MnO2. It is easier to prepare, reacts more efficiently, and the substrate:oxidant ratios are closer to theory.

Another use for barium manganate was as a reagent in the synthesis of the inorganic pigment manganese blue, which is no longer produced on an industrial scale.

Related Research Articles

<span class="mw-page-title-main">Oxidizing agent</span> Chemical compound used to oxidize another substance in a chemical reaction

An oxidizing agent is a substance in a redox chemical reaction that gains or "accepts"/"receives" an electron from a reducing agent. In other words, an oxidizer is any substance that oxidizes another substance. The oxidation state, which describes the degree of loss of electrons, of the oxidizer decreases while that of the reductant increases; this is expressed by saying that oxidizers "undergo reduction" and "are reduced" while reducers "undergo oxidation" and "are oxidized". Common oxidizing agents are oxygen, hydrogen peroxide, and the halogens.

<span class="mw-page-title-main">Manganese dioxide</span> Chemical compound

Manganese dioxide is the inorganic compound with the formula MnO
2
. This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for MnO
2
is for dry-cell batteries, such as the alkaline battery and the zinc–carbon battery. MnO
2
is also used as a pigment and as a precursor to other manganese compounds, such as KMnO
4
. It is used as a reagent in organic synthesis, for example, for the oxidation of allylic alcohols. MnO
2
has an α-polymorph that can incorporate a variety of atoms in the "tunnels" or "channels" between the manganese oxide octahedra. There is considerable interest in α-MnO
2
as a possible cathode for lithium-ion batteries.

<span class="mw-page-title-main">Potassium permanganate</span> Chemical compound

Potassium permanganate is an inorganic compound with the chemical formula KMnO4. It is a purplish-black crystalline salt, that dissolves in water as K+ and MnO
4
, an intensely pink to purple solution.

<span class="mw-page-title-main">Potassium ferrate</span> Chemical compound

Potassium ferrate is the chemical compound with the formula K2FeO4. This purple salt is paramagnetic, and is a rare example of an iron(VI) compound. In most of its compounds, iron has the oxidation state +2 or +3 (Fe2+ or Fe3+). Reflecting its high oxidation state, FeO2−4 is a powerful oxidizing agent.

<span class="mw-page-title-main">Manganese(III) fluoride</span> Chemical compound

Manganese(III) fluoride (also known as Manganese trifluoride) is the inorganic compound with the formula MnF3. This red/purplish solid is useful for converting hydrocarbons into fluorocarbons, i.e., it is a fluorination agent. It forms a hydrate and many derivatives.

<span class="mw-page-title-main">Permanganate</span> Chemical compound

A permanganate is a chemical compound with the manganate(VII) ion, MnO
4
, the conjugate base of permanganic acid. Because the manganese atom has a +7 oxidation state, the permanganate(VII) ion is a strong oxidising agent. The ion is a transition metal ion with a tetrahedral structure. Permanganate solutions are purple in colour and are stable in neutral or slightly alkaline media. The exact chemical reaction depends on the carbon-containing reactants present and the oxidant used. For example, trichloroethane (C2H3Cl3) is oxidised by permanganate ions to form carbon dioxide (CO2), manganese dioxide (MnO2), hydrogen ions (H+), and chloride ions (Cl).

<span class="mw-page-title-main">Potassium superoxide</span> Chemical compound

Potassium superoxide is an inorganic compound with the formula KO2. It is a yellow paramagnetic solid that decomposes in moist air. It is a rare example of a stable salt of the superoxide anion. It is used as a CO2 scrubber, H2O dehumidifier, and O2 generator in rebreathers, spacecraft, submarines, and spacesuits.

<span class="mw-page-title-main">Manganate</span> Chemical compound

In inorganic nomenclature, a manganate is any negatively charged molecular entity with manganese as the central atom. However, the name is usually used to refer to the tetraoxidomanganate(2−) anion, MnO2−
4
, also known as manganate(VI) because it contains manganese in the +6 oxidation state. Manganates are the only known manganese(VI) compounds.

<span class="mw-page-title-main">Sodium manganate</span> Chemical compound

Sodium manganate is the inorganic compound with the formula Na2Mn O4. This deep green solid is a rarely encountered analogue of the related salt K2MnO4. Sodium manganate is rare because it cannot be readily prepared from the oxidation of manganese dioxide and sodium hydroxide. Instead this oxidation reaction tends to stop at producing sodium hypomanganate, Na3MnO4, and even this Mn(V) salt is unstable in solution. Sodium manganate can be produced by reduction of sodium permanganate under basic conditions:

<span class="mw-page-title-main">Potassium manganate</span> Chemical compound

Potassium manganate is the inorganic compound with the formula K2MnO4. This green-colored salt is an intermediate in the industrial synthesis of potassium permanganate, a common chemical. Occasionally, potassium manganate and potassium permanganate are confused, but each compound's properties are distinct.

<span class="mw-page-title-main">Tetrapropylammonium perruthenate</span> Chemical compound

Tetrapropylammonium perruthenate (TPAP or TPAPR) is the chemical compound described by the formula N(C3H7)4RuO4. Sometimes known as the Ley–Griffith reagent, this ruthenium compound is used as a reagent in organic synthesis. This salt consists of the tetrapropylammonium cation and the perruthenate anion, RuO−4.

Ruthenium tetroxide is the inorganic compound with the formula RuO4. It is a yellow volatile solid that melts near room temperature. It has the odor of ozone. Samples are typically black due to impurities. The analogous OsO4 is more widely used and better known. It is also the anhydride of hyperruthenic acid (H2RuO5). One of the few solvents in which RuO4 forms stable solutions is CCl4.

In chemistry, hypomanganate, also called manganate(V) or tetraoxidomanganate(3−), is a trivalent anion (negative ion) composed of manganese and oxygen, with formula MnO3−
4
.

Potassium hypomanganate is the inorganic compound with the formula K3MnO4. Also known as potassium manganate(V), this bright blue solid is a rare example of a salt with the hypomanganate or manganate(V) anion, where the manganese atom is in the +5 oxidation state. It is an intermediate in the production of potassium permanganate and the industrially most important Mn(V) compound.

<span class="mw-page-title-main">Barium ferrate</span> Chemical compound

Barium ferrate is the chemical compound of formula BaFeO4. This is a rare compound containing iron in the +6 oxidation state. The ferrate(VI) ion has two unpaired electrons, making it paramagnetic. It is isostructural with BaSO4, and contains the tetrahedral [FeO4]2− anion.

Alcohol oxidation is a collection of oxidation reactions in organic chemistry that convert alcohols to aldehydes, ketones, carboxylic acids, and esters where the carbon carries a higher oxidation state. The reaction mainly applies to primary and secondary alcohols. Secondary alcohols form ketones, while primary alcohols form aldehydes or carboxylic acids.

<span class="mw-page-title-main">Pentacarbonylhydridomanganese</span> Chemical compound

Pentacarbonylhydridomanganese is an organometallic compound with formula HMn(CO)5. This compound is one of the most stable "first-row" transition metal hydrides.

Oxidation with chromium(VI) complexes involves the conversion of alcohols to carbonyl compounds or more highly oxidized products through the action of molecular chromium(VI) oxides and salts. The principal reagents are Collins reagent, PDC, and PCC. These reagents represent improvements over inorganic chromium(VI) reagents such as Jones reagent.

<span class="mw-page-title-main">Jones oxidation</span> Oxidation of alcohol

The Jones oxidation is an organic reaction for the oxidation of primary and secondary alcohols to carboxylic acids and ketones, respectively. It is named after its discoverer, Sir Ewart Jones. The reaction was an early method for the oxidation of alcohols. Its use has subsided because milder, more selective reagents have been developed, e.g. Collins reagent.

Barium permanganate is a chemical compound, with the formula Ba(MnO4)2. It forms violet to brown crystals that are sparingly soluble in water.

References

  1. Olsen, J. C. (1900). Permanganic Acid by Electrolysys. Easton, PA: The Chemical Publishing Company.
  2. Garry Procter, Steven V. Ley, Grant H. Castle, "Barium Manganate" Encyclopedia of Reagents for Organic Synthesis 2001. doi : 10.1002/047084289X.rb003
  3. Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford:Pergamon Press. Vol. 15, "Manganese Compounds". ISBN   0-08-022057-6.
  4. Jellinek, F. J. Inorg. Nucl. Chem. 1960. 13, 329-331. {{doi: 10.1016/0022-1902(60)80316-8}}
  5. 1 2 Firouzabadi, H.; Mostafavipoor,Z. (1983), "Barium Manganate. A Versatile Oxidant in Organic Synthesis", Bull. Chem. Soc. Jpn. 56 (3): p914-917. {{doi: 10.1246/bcsj.56.914}}.
  6. Carrington, A.; Symons, M. C. R. "Structure and reactivity of the oxy-anions of transition metals. Part I. The managese oxy-anions", J. Chem. Soc. 1956, p3373-3380. doi : 10.1039/JR9560003373.
  7. Procter.G.; Ley, S. V.; Castle, G.H. (2004), "Barium Manganate", in Paquette,L., Encyclopedia of Reagents for Organic Synthesis, New York:Wiley, {{doi:10.1002/047084289X}}.