The chemistry and scope of holmium  and holmium compounds is reviewed here. We manufacture all these compounds and in most instances with these rare earth products , it is important to know the method of manufacture, solubilities, assays and trace impurities.

Rare earth compounds were named not because the individual rare earth elements are rare but because each individual rare earth element rarely exists as a single element but as a mixture of rare earth elements. In 1878 Per Teodor  discovered the element while he was working on erbia earth erbium oxide. Using the method developed by Carl  Gustaf Mosander, Cleve first removed all of the known contaminants from erbia. The result of that effort was two new materials, one brown and one green. He named the brown substance holmia (after the Latin name for Cleve's home town, Stockholm) and the green one thulia. Holmia was later found to be the holmium oxide and thulia was thulium oxide.

The composition of monozite ore is the basis for rare earth impurities found in holmium compounds and the level of impurities is directly related to the separation and source of these ores. It is commercially extracted via ion exchange from monazite sand (0.05% holmium) but is still difficult to separate from other rare earths. The element has been isolated through the reduction of its anhydrous chlorid or fluoride with metallic calcium. Its estimated abundance in the earth's crust is 1.3 mg/kg. Holmium obeys the Oddo-Harkins rule: as an odd-numbered element, it is less abundant than its immediate even-numbered neighbors, dysprosium and erbium. However, it is the most abundant of the odd-numbered heavy lanthanides. The principal current source are some of the ion-adsorption clays of southern China. Some of these have a rare earth composition similar to that found in xenotime or gadolinite.

Level of impurities:

 99.9%(REO)  1000ppm total rare earth oxide impurities

99.99%(REO)  100ppm total rare earth oxide impurities

99.999%(REO)  10ppm total rare earth oxide impurities

99.9999%(REO)  1ppm total rare earth oxide impurities

For a certificate of analysis for any of these products ordered contact: techservice@rareearthproducts.com

Holmium chloride, bromide and nitrates are isolated as the hexahydrates and are very soluble in water. Anhydrous halides are also available. Holmium acetate is somewhat soluble in water. (It is important to work with the manufacturer of your rare earth products because in the case of acetates the solubility varies widely depending on the method of manufacture and reaction conditions.

A new exciting holmium compound is holmium trifluoroacetate which is very soluble in water and has new uses as a catalyst in organic synthesis. Holmium oxalate, carbonate and sulfate are insoluble in water and exist as a defined hydrate. These compounds can also be hydrated.

Another example of purchasing rare earth compounds from a known manufacturer is holmium fluoride. The rare earth fluorides are used in advanced material  films, lens and glasses. In virtually all applications the fluoride should be carbonate free. Rare Earth Products, Inc. uses a proprietary process to make carbonate free rare earth fluorides.

Rare Earth Products, Inc makes the most extensive list of rare earth metal beta diketonates. These organometallic compounds are used for MOCVD, spin coating, catalysts and NMR shift reagents to name a few advanced applications. The compounds offered include rare earth metal complexes with :

acetylacetonate or 2,4-pentanedionate ACAC

 hepatfluorodimethyloctanedionate FOD

hexafluoroacetylacetonate HFAC

tetrametylheptanedionate TMHD

  trifluroacetylacetonate TFAC

chiral ligands OPT etc

 Most of these compounds are used because of  the physical vapor pressure, volatility and organic solvent solubility. Contact our technical service department to get physical data such as melting points, sublimation temperatures,  solubility,  boiling points,  etc - techservice@rareearthproducts.com.

Rare Earth Products, Inc also manufactures the organic soluble compounds holmium 2-ethylhexanoate and holmium cyclohexanebutyrate. These metal organic compounds are soluble in organic solvents. We can also custom synthesize various rare earth compounds by adding various ligands, dehydrating and coordinating various organic solvents to enhance non polar solubility. Contact techservice@rareearthproducts.com.

The intermetallics holmium sulfide, holmium selenide and holmium telluride are available upon request. Holmium trifluoromethanesulfonate or holmium triflate is available and useful as a Friedel -Crafts catalyst as the anhydrous salt or the hydrate. A new compound holmium thenoyltrifluoroacetonate is used as a thermal laser dye.