Holmium compounds

Few holmium compounds have any important commercial uses. The one exception is holmium oxide (H02O3), used to add a yellowish color to glass, in the manufacture of refractory materials, and as a catalyst for some chemical reactions. A refractory material is a material that can withstand very high temperatures and reflect heat back away from itself A catalyst is a substance used to speed up a chemical reaction without undergoing any change itself In 2007, the price of holmium oxide was approximately 750 per kilogram. 

T-Ray data indicate that BiPsOi4 is an isotype of the ultraphosphate LaP50j4, and there are strong structural relations with the holmium compound. The latter can be obtained in both orthorhombic Pnmd) and monoclinic (C2Jc) forms, and the ultraphosphate structure for both is shown by single-crystal measurements. ... 

The bis(methylcyclopentadienyl) rare earth chorides of gadolinium, erbium and ytterbium have been prepared according to eq. (17) as colorless, pink or red crystals. They are monomeric in tetrahydrofuran, but dimeric in benzene solution (Maginn et al., 1963). The corresponding dysprosium and holmium compounds were prepared by Crease and Legzdins (1973b), the yttrium and lutetium derivatives by W.J. Evans et al. (1982a) and characterized by NMR spectroscopy. 

Some nut trees accumulate mineral elements. Hickory nut is notable as an accumulator of aluminum compounds (30) the ash of its leaves contains up to 37.5% of AI2O2, compared with only 0.032% of aluminum oxide in the ash of the Fnglish walnut s autumn leaves. As an accumulator of rare-earth elements, hickory greatly exceeds all other plants their leaves show up to 2296 ppm of rare earths (scandium, yttrium, lanthanum, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium). The amounts of rare-earth elements found in parts of the hickory nut are kernels, at 5 ppm shells, at 7 ppm and shucks, at 17 ppm. The kernel of the Bra2d nut contains large amounts of barium in an insoluble form when the nut is eaten, barium dissolves in the hydrochloric acid of the stomach. 

The compounds of the rare earth elements are usually highly colored. Neodymium s compounds are mainly lavender and violet, samarium s yellow and brown, holmium s yellow and orange, and erbium s rose-pink. Europium makes pink salts which evaporate easily. Dysprosium makes greenish yellow compounds, and ytterbium, yellow-gold. Compounds of lutetium are colorless, and compounds of terbium are colorless, dark brown, or black. 

On the other hand, lanthanides with 100% isotopical purity such as terbium or holmium are preferred to simplify the operation and minimize decoherence in spin qubits. In this respect, the existence, for some lanthanides, of a manifold of electronuclear states can provide additional resources for the implementation of multiple qubit states within the same molecule [31]. All atoms in the first coordination sphere should be oxygen, and the sample should be deuter-ated if the compound contains hydrogen, to avoid interaction with other nuclei spins. Again, POM chemistry has been shown to provide ideal examples of this kind. 

Holmium has an oxidation state of +3 that, on a limited basis, can form a few compounds with the halogens and oxygen. They are of no commercial uses, and most holmium is used for research purposes. 

Holmium forms all its compounds in -i-3 valence state. The metal forms fluoride, hydroxide, phosphate, oxalate, and carbonate that are insoluble in water. Its water-soluble salts are chloride, bromide, iodide, acetate, nitrate and sulfate. 

Hohnium oxide occurs in nature, usually associated with small quantities of other rare-earth oxides. Commercial applications of this compound have not been explored fuUy. It is used in refractories and as a catalyst. Characteristic spectral emission lines of holmium oxide glass are used to cahbrate spectrophotometers. ... 

Ho-CuSb. A ternary compound of holmium with copper and antimony of the 3 3 4 stoichiometric ratio was identified and studied by means of an X-ray analysis by Skoloz-... 

The only complexes of lanthanum or cerium to be described are [La(terpy)3][C104]3 175) and Ce(terpy)Cl3 H20 411). The lanthanum compound is a 1 3 electrolyte in MeCN or MeN02, and is almost certainly a nine-coordinate mononuclear species the structure of the cerium compound is not known with any certainty. A number of workers have reported hydrated 1 1 complexes of terpy with praseodymium chloride 376,411,438), and the complex PrCl3(terpy)-8H20 has been structurally characterized 376). The metal is in nine-coordinate monocapped square-antiprismatic [Pr(terpy)Cl(H20)5] cations (Fig. 24). Complexes with a 1 1 stoichiometry have also been described for neodymium 33, 409, 411, 413, 417), samarium 33, 411, 412), europium 33, 316, 411, 414, 417), gadolinium 33, 411), terbium 316, 410, 414), dysprosium 33, 410, 412), holmium 33, 410), erbium 33, 410, 417), thulium 410, 412), and ytterbium 410). The 1 2 stoichiometry has only been observed with the later lanthanides, europium 33, 411, 414), gadolinium, dysprosium, and erbium 33). 

V = 1.6874 (4) nm, and Z = 1. The compound is a square antiprism, consisting of the cen-trosymmetric dinuclear [H02(15)4(H2O)4(OH)2]4 cation, uncoordinated 15 molecules, and nitrate anions. The holmium atom is eight-coordinate with four nitrogens from the 15 ligands, two oxygens from H2O molecules, and two oxygens from hydroxo groups. 

Lanthanide (III) Oxides. The lanthanide(III) oxides will be used to illustrate the present breadth of our most extensive knowledge of the chemical thermodynamics of lanthanide compounds. Cryogenic heat capacities of hexagonal (III) lanthanum, neodymium, and samarium oxides, together with those of cubic (III) oxides of gadolinium, dysprosium, holmium, erbium, and ytterbium, have been reported (90, 91, 195). In addition, those of thulium, lutetium, and a composition approaching that of cerium (III) oxide have also been determined, and five well-characterized compositions between PrOi.714 and PrOi.833 are currently under study (J93). 

Element 39, with 4d 5s2 electron configuration, is also similar to the lanthanides. It occurs with the lanthanides in minerals the best source is xenotime, YPO4. Yttrium has properties approximately midway between those of Sc and La its compounds also resemble those of the heavy earths dysprosium and holmium, the ionic radius (0.90 A) being similar. 

Holmium was discovered by Swedish chemist Per Teodor Cleve (1840-1905) in 1879. He named the element after his birthplace, Stockholm, Sweden. Holmium occurs with other rare earth elements in minerals such as monazite and gadolinite. ft can now be separated from other rare earth elements somewhat easily. But no major uses have been found for it or its compounds. 

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