Erbium compounds are compounds containing the element

erbium Erbium is a chemical element with the symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. It is a lanthanide, a rare-earth element, orig ...

(Er). These compounds are usually dominated by erbium in the +3 oxidation state, although the +2, +1 and 0Yttrium and all lanthanides except Ce and Pm have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see and

oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. ...

s have also been reported.

Oxides

Erbium(III) oxide Erbium(III) oxide is the inorganic compound with the formula . It is a pink paramagnetic solid. It finds uses in various optical materials. Structure Erbium(III) oxide has a cubic structure resembling the bixbyite motif. The Er3+ centers are o ...

(also known as erbia) is the only known oxide of erbium, first isolated by

Carl Gustaf Mosander Carl Gustaf Mosander (10 September 1797 – 15 October 1858) was a Swedish chemist. He discovered the rare earth elements lanthanum, erbium and terbium. Early life and education Born in Kalmar, Mosander attended school there until he moved t ...

in 1843, and first obtained in pure form in 1905 by

Georges Urbain Georges Urbain (12 April 1872 – 5 November 1938) was a French chemist, a professor of the Sorbonne, a member of the Institut de France, and director of the Institute of Chemistry in Paris. Much of his work focused on the rare earths, isolating a ...

and Charles James. It has a

cubic Cubic may refer to: Science and mathematics * Cube (algebra), "cubic" measurement * Cube, a three-dimensional solid object bounded by six square faces, facets or sides, with three meeting at each vertex ** Cubic crystal system, a crystal system ...

structure resembling the

bixbyite Bixbyite is a manganese iron oxide mineral with chemical formula: (Mn,Fe)2O3. The iron/manganese ratio is quite variable and many specimens have almost no iron. It is a metallic dark black with a Mohs hardness of 6.0 - 6.5. It is a somewhat rare ...

motif. The Er³⁺ centers are octahedral. The formation of erbium oxide is accomplished by burning erbium metal. Erbium oxide is insoluble in water and soluble in mineral acids.

Halides

Erbium(III) fluoride Erbium(III) fluoride is the fluoride of erbium, a rare earth metal, with the chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical c ...

is a pinkish powder that can be produced by reacting

erbium(III) nitrate Erbium(III) nitrate is an inorganic compound, a salt of erbium and nitric acid with the chemical formula Er(NO3)3. The compound forms pink crystals, readily soluble in water, also forms crystalline hydrates. Synthesis Dissolving metallic erbium in ...

and

ammonium fluoride Ammonium fluoride is the inorganic compound with the formula NH4F. It crystallizes as small colourless prisms, having a sharp saline taste, and is highly soluble in water. Like all fluoride salts, it is moderately toxic in both acute and chronic o ...

. It can be used to make infrared light-transmitting materials and up-converting luminescent materials. Erbium(III) chloride is a violet compounds that can be formed by first heating erbium(III) oxide and ammonium chloride to prouce the

ammonium The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaternar ...

salt of the pentachloride ( H₄sub>2ErCl₅) then heating it in a vacuum at 350-400 ºC. It forms crystals of the type, with

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic ...

crystals and the

point group In geometry, a point group is a mathematical group of symmetry operations ( isometries in a Euclidean space) that have a fixed point in common. The coordinate origin of the Euclidean space is conventionally taken to be a fixed point, and every ...

''C''2/m.Erbium(III) chloride hexahydrate also forms monoclinic crystals with the point group of ''P''2/''n'' (''P''2/''c'') - ''C''⁴_2h. In this compound, erbium is octa-coordinated to form ions with the isolated completing the structure.

Erbium(III) bromide Erbium(III) bromide is a chemical compound with the chemical formula Er Br3 crystal which is highly soluble in water. It is used, like other metal bromide compounds, in water treatment, chemical analysis and for certain crystal growth application ...

is a violet solid. It is used, like other metal bromide compounds, in water treatment, chemical analysis and for certain crystal growth applications.

Erbium(III) iodide Erbium(III) iodide is an iodide of lanthanide metal erbium Erbium is a chemical element with the symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with ...

is a slightly pink compound that is insoluble in water. It can be prepared by directly reacting erbium with

iodine Iodine is a chemical element with the Symbol (chemistry), symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , ...

Borides

Erbium tetraboride Erbium tetraboride is a boride of the lanthanide metal erbium. It is hard and has a high melting point. Industrial applications of erbium boride include use in semiconductors, the blades of gas turbines, and the nozzles A nozzle is a device ...

is a

boride A boride is a compound between boron and a less electronegative element, for example silicon boride (SiB3 and SiB6). The borides are a very large group of compounds that are generally high melting and are covalent more than ionic in nature. Some b ...

of erbium. It is hard and has a high melting point. It can be used in

semiconductor A semiconductor is a material which has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way. ...

s, the blades of

gas turbines A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directio ...

, and the nozzles of rocket engines.

Erbium hexaboride Erbium hexaboride (ErB6) is a rare-earth hexaboride compound containing the element erbium, which has a calcium hexaboride crystal structure. It is one of the fundamental compounds formed in reactions between erbium and boron. The compound is is ...

is another boride of erbium, with a

calcium hexaboride Calcium hexaboride (sometimes calcium boride) is a compound of calcium and boron with the chemical formula CaB6. It is an important material due to its high electrical conductivity, hardness, chemical stability, and melting point. It is a black, l ...

structure. It is

isostructural Isostructural chemical compounds have similar chemical structures. "Isomorphous" when used in the relation to crystal structures is not synonymous: in addition to the same atomic connectivity that characterises isostructural compounds, isomorphous s ...

with all other rare-earth hexaboride compounds including lanthanum hexaboride, samarium hexaboride, and cerium hexaboride.

Other compounds

Erbium(III) hydroxide Erbium(III) hydroxide is an inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a sub ...

is a pink solid that decomposes to ErO(OH) at an elevated temperature, then further heating will produce erbium(III) oxide. Erbium(III) phosphide (ErP) is also a pink solid that can be formed by the direct reaction of its constituent elements. It forms crystals of a

cubic system In crystallography, the cubic (or isometric) crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals. There are three main varieties of ...

space group In mathematics, physics and chemistry, a space group is the symmetry group of an object in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of an object that leave it ...

''Fm''3''m''.

Erbium(III) nitrate Erbium(III) nitrate is an inorganic compound, a salt of erbium and nitric acid with the chemical formula Er(NO3)3. The compound forms pink crystals, readily soluble in water, also forms crystalline hydrates. Synthesis Dissolving metallic erbium in ...

(Er(NO₃)₃) forms pink crystals. It is readily soluble in water and forms crystalline hydrates.

Erbium(III) acetate Erbium(III) acetate is the acetate salt of erbium, with the proposed chemical formula of Er(CH3COO)3. It can be used to synthesize some optical materials. Physical properties The tetrahydrate of erbium(III) acetate is thermally decomposed at 90 ...

is a light pink solid that is used to synthesize some optical materials. The tetrahydrate of erbium(III) acetate is thermally decomposed at 90 °C, giving a proposed anhydride: : Er(CH₃COO)₃·4H₂O → Er(CH₃COO)₃ + 4 H₂O Continuing heating to 310 °C will form

ketene In organic chemistry, a ketene is an organic compound of the form , where R and R' are two arbitrary monovalent chemical groups (or two separate substitution sites in the same molecule). The name may also refer to the specific compound eth ...

: : Er(CH₃COO)₃ → Er(OH)(CH₃COO)₂ + CH₂=C=O At 350 °C, the proposed Er(OH)(CH₃COO)₂ loses

acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main componen ...

to yield a material of the formula ErOCH₃COO, forming Er₂O₂CO₃ at 390 °C, finally obtaining Er₂O₃ at 590 °C.

Organoerbium compounds

Organoerbium compounds are very similar to those of the other lanthanides, as they all share an inability to undergo

π backbonding In chemistry, π backbonding, also called π backdonation, is when electrons move from an atomic orbital on one atom to an appropriate symmetry antibonding orbital on a ''π-acceptor ligand''. It is especially common in the organometallic che ...

. They are thus mostly restricted to the mostly ionic

cyclopentadienide In chemistry, the cyclopentadienyl anion or cyclopentadienide is an aromatic species with a formula of and abbreviated as Cp−. It is formed from the deprotonation of the molecule cyclopentadiene. Properties The cyclopentadienyl anion ...

s (isostructural with those of lanthanum) and the σ-bonded simple alkyls and aryls, some of which may be polymeric.Greenwood and Earnshaw, pp. 1248–9

References