chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...

, metal hydroxides are a family of compounds of the form where M is a

metal A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, electricity and thermal conductivity, heat relatively well. These properties are all associated wit ...

. They consist of

hydroxide Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a single covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. It ...

()

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...

s and metallic

cation An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

s, and are often strong bases. Some metal hydroxides, such as

alkali metal The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K),The symbols Na and K for sodium and potassium are derived from their Latin names, ''natrium'' and ''kalium''; these are still the origins of the names ...

hydroxides,

ionize Ionization or ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule i ...

completely when dissolved. Certain metal hydroxides are weak

electrolyte An electrolyte is a substance that conducts electricity through the movement of ions, but not through the movement of electrons. This includes most soluble Salt (chemistry), salts, acids, and Base (chemistry), bases, dissolved in a polar solven ...

s and dissolve only partially in

aqueous solution An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, also known as sodium chloride (NaCl), in water ...

Examples

Aluminium hydroxide Aluminium hydroxide, , is found as the mineral gibbsite (also known as hydrargillite) and its three much rarer polymorphs: bayerite, doyleite, and nordstrandite. Aluminium hydroxide is amphoteric, i.e., it has both basic and acidic propert ...

Beryllium hydroxide Beryllium hydroxide, Be(OH)2, is an amphoteric hydroxide, dissolving in both acids and alkalis. Industrially, it is produced as a by-product in the extraction of beryllium metal from the ores beryl and bertrandite. The natural pure beryllium hydro ...

Cobalt(II) hydroxide Cobalt(II) hydroxide or cobaltous hydroxide is the inorganic compound with the formula , consisting of divalent cobalt cations and hydroxide anions . The pure compound, often called the "beta form" (β-) is a pink solid insoluble in water. The n ...

Copper(II) hydroxide Copper(II) hydroxide is the hydroxide of copper with the chemical formula of Cu(OH)2. It is a pale greenish blue or bluish green solid. Some forms of copper(II) hydroxide are sold as "stabilized" copper(II) hydroxide, although they likely consist ...

* Curium hydroxide *

Gold(III) hydroxide Gold(III) hydroxide, gold trihydroxide, or gold hydroxide is an inorganic compound, a hydroxide of gold Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright ...

Iron(II) hydroxide Iron (II) hydroxide or ferrous hydroxide is an inorganic compound with the formula Fe(OH)2. It is produced when iron (II) salts, from a compound such as iron(II) sulfate, are treated with hydroxide ions. Iron(II) hydroxide is a white solid, but ev ...

* Mercury(II) hydroxide *

Nickel(II) hydroxide Nickel(II) hydroxide is the inorganic compound with the formula Ni(OH)2. It is a lime-green solid that dissolves with decomposition in ammonia and amines and is attacked by acids. It is electroactive, being converted to the Ni(III) oxy-hydroxide ...

Tin(II) hydroxide Tin(II) hydroxide, Sn(OH)2, also known as ''stannous hydroxide'', is an inorganic compound tin(II). The only related material for which definitive information is available is the oxy hydroxide Sn6O4(OH)4, but other related materials are claimed. T ...

Uranyl hydroxide Uranyl hydroxide is a hydroxide of uranium with the chemical formula UO2(OH)2 in the monomeric form and UO2)2(OH)4sup>2- in the dimeric; both forms may exist in normal aqueous media. In aerobic conditions, up to 5 hydroxides can bind to uranyl ( ...

Zinc hydroxide Zinc hydroxide Zn( OH)2 is an inorganic chemical compound. It also occurs naturally as 3 rare minerals: wülfingite (orthorhombic), ashoverite and sweetite (both tetragonal). Like the hydroxides of other metals, such as lead, aluminium, beryl ...

Zirconium(IV) hydroxide Zirconium (IV) hydroxide, often called hydrous zirconia is an ill-defined material or family of materials variously described as and . All are white solids with low solubility in water. These materials are widely employed in the preparation of ...

Lithium hydroxide Lithium hydroxide is an inorganic compound with the formula LiOH. It can exist as anhydrous or hydrated, and both forms are white hygroscopic solids. They are soluble in water and slightly soluble in ethanol. Both are available commercially. While ...

Rubidium hydroxide Rubidium hydroxide is the inorganic compound with the formula RbOH. It consists of rubidium cations and an equal number of hydroxide anions. It is a colorless solid that is commercially available as aqueous solutions from a few suppliers. Like ...

Cesium hydroxide Caesium hydroxide is a strong base (pKa= 15.76) containing the highly reactive alkali metal caesium, much like the other alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. It is the strongest of the five alkali metal hydro ...

Sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...

Potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...

Alkali metal hydroxides

Other metal hydroxides

Gallium(III) hydroxide Gallium hydroxide is an inorganic compound with the chemical formula . It is formed as a gel following the addition of ammonia to salts.Anthony John Downs, (1993), ''Chemistry of Aluminium, Gallium, Indium, and Thallium'', Springer, It is also ...

Lead(II) hydroxide Lead(II) hydroxide is an inorganic compound with the formula . The material has not been isolated but its existence has been inferred as an ill-defined component of solutions of Pb(II). "Lead does not appear to form a simple hydroxide, Pb(OH)2," ...

Thallium(I) hydroxide Thallium(I) hydroxide, also called thallous hydroxide, is a chemical compound with the chemical formula . It is a hydroxide of thallium, with thallium in oxidation state +1. It is a thallium(I) salt of water. It consists of thallium(I) cations and ...

Thallium(III) hydroxide Thallium(III) hydroxide, , also known as thallic hydroxide, is a hydroxide of thallium. It is a white solid. Thallium(III) hydroxide is a very weak base; it dissociates to give the thallium(III) ion, , only in strongly acidic conditions. Prepara ...

Molecular metal hydroxides

Many metal hydroxides are in fact complexes, i.e. molecules or ions. The

transition metal hydroxide complexes Transition metal hydroxide complexes are coordination complexes containing one or more hydroxide (OH−) ligands. The inventory is very large. Hydroxide as a ligand Hydroxide is classified as an X ligand in the Covalent bond classification method. ...

are a well developed area in

coordination chemistry A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ' ...

Role in soils

soil Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...

s, it is assumed that larger amounts of

natural phenol In biochemistry, naturally occurring phenols are natural products containing at least one phenol functional group. Phenolic compounds are produced by plants and microorganisms. Organisms sometimes synthesize phenolic compounds in response to ecol ...

s are released from decomposing

plant litter Plant litter (also leaf litter, tree litter, soil litter, litterfall, or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that has fallen to the ground. This detritus or dead organic material and its constituent ...

rather than from throughfall in any natural plant community. Decomposition of dead plant material causes complex organic compounds to be slowly oxidized (

lignin Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidit ...

-like

humus In classical soil science, humus is the dark organic matter in soil that is formed by the decomposition of plant and animal matter. It is a kind of soil organic matter. It is rich in nutrients and retains moisture in the soil. Humus is the Lati ...

) or to break down into simpler forms (sugars and amino sugars, aliphatic and phenolic organic acids), which are further transformed into microbial biomass (microbial humus) or are reorganized, and further oxidized, into humic assemblages (

fulvic Humic substances (HS) are colored relatively recalcitrant organic compounds naturally formed during long-term decomposition and transformation of biomass residues. The color of humic substances varies from bright yellow to light or dark brown lead ...

and

humic Humic substances (HS) are colored relatively recalcitrant organic compounds naturally formed during long-term decomposition and transformation of biomass residues. The color of humic substances varies from bright yellow to light or dark brown lead ...

acids), which bind to

clay mineral Clay minerals are hydrous aluminium phyllosilicates (e.g. kaolin, Al2 Si2 O5( OH)4), sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations found on or near some planetary surfaces. Clay minera ...

s and metal hydroxides.

References

Metals Hydroxides {{Base-stub