The key difference between manganese oxide and manganese dioxide is that manganese oxide appears as green crystals, whereas manganese dioxide appears as brown or black solid.
Manganese oxide and manganese dioxide are inorganic oxide compounds having manganese atoms attached to oxygen atoms. Both these compounds have different important applications.
CONTENTS
1. Overview and Key Difference
2. What is Manganese Oxide
3. What is Manganese Dioxide
4. Manganese Oxide vs Manganese Dioxide in Tabular Form
5. Summary – Manganese Oxide vs Manganese Dioxide
What is Manganese Oxide?
Manganese oxide is a chemical compound having the chemical formula MnO. However, we can use this term to refer to any oxide or hydroxide of manganese, including manganese(II) oxide, manganese(II,III) oxide, manganese dioxide, and manganese(VI) oxide.
Figure 01: Manganese Oxide
Manganese oxide appears as green crystals, and it is produced on a large scale to be used as a component in fertilizers and food additives. Similar to other monoxides, MnO also adopts the rock salt structure, which is given in the above image. It has cations and anions, both octahedrally coordinated. Also, similar to many oxides, MnO is often nonstoichiometric and can have a varying composition (range from MnO to MnO1.045).
The molar mass of manganese oxide is 70.93 g/mol. It has a density of about 5.43 g/mol. The melting point is 1945 degrees Celsius, and it is insoluble in water. However, MnO is soluble in acids. The crystal structure of this compound can be described as a halite structure.
What is Manganese Dioxide?
Manganese dioxide is an inorganic compound having the chemical formula MnO2. It appears as a black-brown solid substance and naturally occurs as the mineral pyrolusite. It is the main ore of manganese, and it also occurs as a component of manganese nodules.
Figure 02: Manganese Dioxide
The molar mass of manganese dioxide is 86.93 g/mol, and the density is 5.026 g/cm3. The melting point is about 535 degrees Celsius, and at higher temperatures, it tends to decompose. However, it is insoluble in water. The crystal structure of manganese dioxide is tetragonal.
There are several polymorphs of MnO2 as well as a hydrated form. Similar to many other dioxides, this substance crystallizes in the rutile crystal structure, having 3 coordinate oxide and octahedral metal centers. This substance is characteristically nonstoichiometric because it lacks oxygen. Moreover, in organic synthesis reactions, we need this substance in a freshly-prepared state. The crystal structure of this compound has a very open structure consisting of channels that accommodate metal atoms, including silver and barium.
What is the Difference Between Manganese Oxide and Manganese Dioxide?
Manganese oxide and manganese dioxide are important inorganic compounds formed from the oxidation of manganese chemical elements. The key difference between manganese oxide and manganese dioxide is that manganese oxide appears as green crystals, whereas manganese dioxide appears as brown or black solid. In manganese oxide, the oxidation state of manganese is +2, while in manganese dioxide, the oxidation state of manganese is +4. Moreover, manganese oxide has a tetragonal crystal structure whereas manganese dioxide has a halite crystal structure.
The below infographic presents the differences between manganese oxide and manganese dioxide in tabular form for side-by-side comparison.
Summary – Manganese Oxide vs Manganese Dioxide
Manganese oxide and manganese dioxide are oxides of manganese. However, the term manganese oxide is sometimes used as a collective name to refer to all the oxides and hydroxides made by manganese chemical elements. The key difference between manganese oxide and manganese dioxide is that manganese oxide appears as green crystals, whereas manganese dioxide appears as brown or black solid.
Reference:
1. “Manganese Oxide.” An Overview | ScienceDirect Topics.
Image Courtesy:
1. “Manganese(II)-oxide-xtal-3D-SF” By CCoil (talk) – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Manganese(IV) oxide” By Walkerma assumed – No machine-readable source provided. Own work assumed (based on copyright claims). (Public Domain) via Commons Wikimedia