Erbium compounds are compounds containing the element

erbium Erbium is a chemical element; it has Symbol (chemistry), 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- ...

(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 Electrical charge, charge of an atom if all of its Chemical bond, bonds to other atoms are fully Ionic bond, ionic. It describes the degree of oxidation (loss of electrons ...

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 move ...

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 ...

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 w ...

structure resembling the

bixbyite Bixbyite is a manganese iron oxide mineral with chemical formula: . 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 mineral ...

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 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 Erbium(III) chloride is a violet solid with the formula . It is used in the preparation of erbium metal. Preparation Anhydrous erbium(III) chloride can be produced by the ammonium chloride route. In the first step, erbium(III) oxide is heated ...

is a violet compounds that can be formed by first heating erbium(III) oxide and

ammonium chloride Ammonium chloride is an inorganic chemical compound with the chemical formula , also written as . It is an ammonium salt of hydrogen chloride. It consists of ammonium cations and chloride anions . It is a white crystalline salt (chemistry), sal ...

to produce the

ammonium Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged (cationic) polyatomic ion, molecular ion with the chemical formula or . It is formed by the protonation, addition of a proton (a hydrogen nucleu ...

salt of the pentachloride ( H₄sub>2ErCl₅) then heating it in a vacuum at 350-400 °C. 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 Vector (geometric), vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in t ...

crystals and the

point group In geometry, a point group is a group (mathematics), mathematical group of symmetry operations (isometry, isometries in a Euclidean space) that have a Fixed point (mathematics), fixed point in common. The Origin (mathematics), coordinate origin o ...

''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 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; it has Symbol (chemistry), symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemica ...

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; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a vi ...

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 with electrical conductivity between that of a conductor and an insulator. Its conductivity can be modified by adding impurities (" doping") to its crystal structure. When two regions with different doping level ...

s, the blades of

gas turbines A gas turbine or gas turbine engine 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 direction of flow: ...

, and the

nozzles A nozzle is a device designed to control the direction or characteristics of a fluid flow (specially to increase velocity) as it exits (or enters) an enclosed chamber or pipe. A nozzle is often a pipe or tube of varying cross sectional area, ...

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 ...

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 with chemical formula Er(OH)3. Chemical properties Erbium(III) hydroxide reacts with acids An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen cation, H+), known ...

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 a repeating pattern in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of the pattern that ...

''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 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 valence (chemistry), monovalent functional group, chemical groups (or two separate Substituent, substitution sites in the same molecule). The na ...

: : 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 compone ...

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, pi backbonding or π backbonding is a π-bonding interaction between a filled (or half filled) orbital of a transition metal atom and a vacant orbital on an adjacent ion or molecule. In this type of interaction, electrons from the ...

. They are thus mostly restricted to the mostly ionic

cyclopentadienide Sodium cyclopentadienide is an organosodium compound with the formula C5H5Na. The compound is often abbreviated as NaCp, where Cp− is the cyclopentadienide anion. Sodium cyclopentadienide is a colorless solid, although samples often are pin ...

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