Manganese is a chemical element; it has symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. Manganese is a transition metal with a multifaceted array of industrial alloy uses, particularly in stainless steels. It improves strength, workability, and resistance to wear. Manganese oxide is used as an oxidising agent; as a rubber additive; and in glass making, fertilisers, and ceramics. Manganese sulfate can be used as a fungicide.

A pigment is a powder used to add color or change visual appearance. Pigments are completely or nearly insoluble and chemically unreactive in water or another medium; in contrast, dyes are colored substances which are soluble or go into solution at some stage in their use. Dyes are often organic compounds whereas pigments are often inorganic. Pigments of prehistoric and historic value include ochre, charcoal, and lapis lazuli.

Porphyrins are a group of heterocyclic macrocycle organic compounds, composed of four modified pyrrole subunits interconnected at their α carbon atoms via methine bridges (=CH−). In vertebrates, an essential member of the porphyrin group is heme, which is a component of hemoproteins, whose functions include carrying oxygen in the bloodstream. In plants, an essential porphyrin derivative is chlorophyll, which is involved in light harvesting and electron transfer in photosynthesis.

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.

Group 7, numbered by IUPAC nomenclature, is a group of elements in the periodic table. It contains manganese (Mn), technetium (Tc), rhenium (Re) and bohrium (Bh). This group lies in the d-block of the periodic table, and are hence transition metals. This group is sometimes called the manganese group or manganese family after its lightest member; however, the group itself has not acquired a trivial name because it belongs to the broader grouping of the transition metals.

Copper phthalocyanine (CuPc), also called phthalocyanine blue, phthalo blue and many other names, is a bright, crystalline, synthetic blue pigment from the group of dyes based on phthalocyanines. Its brilliant blue is frequently used in paints and dyes. It is highly valued for its superior properties such as light fastness, tinting strength, covering power and resistance to the effects of alkalis and acids. It has the appearance of a blue powder, insoluble in most solvents including water.

Phthalocyanine is a large, aromatic, macrocyclic, organic compound with the formula (C₈H₄N₂)₄H₂ and is of theoretical or specialized interest in chemical dyes and photoelectricity.

Manganese(II) chloride is the dichloride salt of manganese, MnCl₂. This inorganic chemical exists in the anhydrous form, as well as the dihydrate (MnCl₂·2H₂O) and tetrahydrate (MnCl₂·4H₂O), with the tetrahydrate being the most common form. Like many Mn(II) species, these salts are pink, with the paleness of the color being characteristic of transition metal complexes with high spin d⁵ configurations.

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.

Manganese carbonate is a compound with the chemical formula MnCO₃. Manganese carbonate occurs naturally as the mineral rhodochrosite but it is typically produced industrially. It is a pale pink, water-insoluble solid. Approximately 20,000 metric tonnes were produced in 2005.

Phthalocyanine green G, which has many commercial names, is a synthetic green pigment from the group of phthalocyanine dyes, a complex of copper(II) with chlorinated phthalocyanine. It is a soft green powder, which is insoluble in water. It is a bright, high intensity colour used in oil and acrylic based artist's paints, and in other applications.

Manganese(II) sulfate usually refers to the inorganic compound with the formula MnSO₄·H₂O. This pale pink deliquescent solid is a commercially significant manganese(II) salt. Approximately 260,000 tonnes of manganese(II) sulfate were produced worldwide in 2005. It is the precursor to manganese metal and many other chemical compounds. Manganese-deficient soil is remediated with this salt.

Manganese(II,III) oxide is the chemical compound with formula Mn₃O₄. Manganese is present in two oxidation states +2 and +3 and the formula is sometimes written as MnO·Mn₂O₃. Mn₃O₄ is found in nature as the mineral hausmannite.

Manganese(II) oxide is an inorganic compound with chemical formula MnO. It forms green crystals. The compound is produced on a large scale as a component of fertilizers and food additives.

Manganese(II) fluoride is the chemical compound composed of manganese and fluoride with the formula MnF₂. It is a light pink solid, the light pink color being characteristic for manganese(II) compounds. It is made by treating manganese and diverse compounds of manganese(II) in hydrofluoric acid. Like some other metal difluorides, MnF₂ crystallizes in the rutile structure, which features octahedral Mn centers.

Manganese(II) acetate are chemical compounds with the formula Mn(CH₃CO₂)₂·(H₂O)n where n = 0, 2, 4. These materials are white or pale pink solids. Some of these compounds are used as a catalyst and as fertilizer.

Manganese(II) nitrate refers to the inorganic compounds with formula Mn(NO₃)₂·(H₂O)_n. These compounds are nitrate salts containing varying amounts of water. A common derivative is the tetrahydrate, Mn(NO₃)₂·4H₂O, but mono- and hexahydrates are also known as well as the anhydrous compound. Some of these compounds are useful precursors to the oxides of manganese. Typical of a manganese(II) compound, it is a paramagnetic pale pink solid.

Manganese(II) iodide is the chemical compound composed of manganese and iodide with the formula MnI₂(H2O)_n. The tetrahydrate is a pink solid while the anhydrous derivative is beige. Both forms feature octahedral Mn centers. Unlike MnCl₂(H₂O)₄ and MnBr₂(H₂O)₄ which are cis, MnI₂(H₂O)₄ is trans.

YInMn Blue, also known as Oregon Blue or Mas Blue, is an inorganic blue pigment that was discovered by Mas Subramanian and his (then) graduate student, Andrew Smith, at Oregon State University in 2009. The pigment is noteworthy for its vibrant, near-perfect blue color and unusually high NIR reflectance. The chemical compound has a unique crystal structure in which trivalent manganese ions in the trigonal bipyramidal coordination are responsible for the observed intense blue color. Since the initial discovery, the fundamental principles of colour science have been explored extensively by the Subramanian research team at Oregon State University, resulting in a wide range of rationally designed novel green, purple, and orange pigments, all through intentional addition of a chromophore in the trigonal bipyramidal coordination environment.