Holmium acetate
{{short description|Compound of holmium}}
{{Chembox
| Name = Holmium acetate
| ImageFile = Holmium(III) acetate.jpg
| ImageSize =
| ImageAlt =
| IUPACName =
| OtherNames = Holmium(III) acetate
| Section1 = {{Chembox Identifiers
| CASNo = 25519-09-9
| CASNo_Comment = anhydrous
| ChemSpiderID = 147291
| EC_number = 247-066-9
| PubChem = 168384
| StdInChI=1S/3C2H4O2.Ho/c3*1-2(3)4;/h3*1H3,(H,3,4);/q;;;+3/p-3
| StdInChIKey = HWQRVFRWLQGBFV-UHFFFAOYSA-K
| SMILES = CC(=O)[O-].CC(=O)[O-].CC(=O)[O-].[Ho+3]
}}
| Section2 = {{Chembox Properties
| Formula = Ho(CH3COO)3
| MolarMass =
| Appearance = crystals
| Density =
| MeltingPt =
| BoilingPt =
| Solubility = soluble}}
| Section3 = {{Chembox Hazards
| MainHazards =
| FlashPt =
| Autoignition = }}
|Section8={{Chembox Related
| OtherAnions = Holmium oxide
Holmium hydroxide
| OtherCations = Dysprosium acetate
Erbium acetate
| OtherFunction =
| OtherFunction_label = }}
}}
Holmium acetate is the acetate salt of holmium, with a chemical formula of Ho(CH3COO)3 as well as at least one hydrate.
Preparation
Holmium acetate can be obtained by dissolving holmium oxide in hot acetic acid
: Ho2O3 + 6 CH3CO2H → 2 Ho(O2CH3)3 + 3 H2O
Dissolving holmium oxide in acetic acid at a pH of 4 will form the tetrahydrate of holmium acetate (Ho2(CH3COO)6·4H2O):{{cite journal|title=Spectral intensities of holmium acetate single crystals|volume=186|issue=1|pages=135–138|date=1991-08-01|issn=0020-1693|doi=10.1016/S0020-1693(00)87943-8|journal=Inorganica Chimica Acta|author=Anna Mondry, Krystyna Bukietyńska}} The anhydrous material can be obtained by heating the hydrated acetate in acetic acid.
Physical properties and structure
Holmium acetate hemihepthydate decomposes at 105 °C, forming into a hemihydrate, further decomposing at 135 °C into an anhydride. Further adding heat will form Ho(OH)(CH3COO)2, HoO(CH3COO) then Ho2O2CO3, forming holmium oxide at 590 °C.{{cite journal|title=Holmium oxide from holmium acetate, formation and characterization: thermoanalytical studies|volume=56|issue=2|pages=263–272|date=2000-11-01|issn=0165-2370|doi=10.1016/S0165-2370(00)00100-5|journal=Journal of Analytical and Applied Pyrolysis|author=G. A. M. Hussein, B. A. A. Balboul, G. A. H. Mekhemer|bibcode=2000JAAP...56..263H }}
According to X-ray crystallography, anhydrous holmium acetate is a coordination polymer. Each Ho(III) center is nine-coordinate, with two bidentate acetate ligands and the remaining sites occupied by oxygens provided by bridging acetate ligands. The lanthanum and praseodymium compounds are isostructural.{{cite journal |doi=10.1002/zaac.19946200306 |date=1994 |volume=620 |issue=3 |last1=Lossin |first1=Adalbert |last2=Meyer |first2=Gerd |title=Pr(CH3COO)3, ein wasserfreies Selten-Erd-Acetat mit Netzwerkstruktur |journal=Zeitschrift für Anorganische und Allgemeine Chemie |pages=438–443 }} In a second polymorph, holmium acetate has 8-coordination.{{cite journal |doi=10.1002/zaac.19936190917 |date=1993 |volume=619 |issue=9 |last1=Lossin |first1=Adalbert |last2=Meyer |first2=Gerd |title=Wasserfreie Selten-Erd-Acetate, M(CH3COO)3 (M = Sm-Lu, Y) mit Kettenstruktur. Kristallstrukturen von Lu(CH3COO)3 und Ho(CH3COO)3 |journal=Zeitschrift für Anorganische und Allgemeine Chemie |pages=1609–1615 }} A tetrahydrate has also been crystallized.{{cite journal |doi=10.1107/S0567740879005987 |title=Holmium triacetate tetrahydrate |date=1979 |last1=Bats |first1=J. W. |last2=Kalus |first2=R. |last3=Fuess |first3=H. |journal=Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry |volume=35 |issue=5 |pages=1225–1227 |bibcode=1979AcCrB..35.1225B }}
Applications
Holmium acetate is used in the manufacture of ceramics, glass, phosphors, metal halide lamps, and as a dopant in garnet lasers. It is also used in nuclear reactors to keep the chain reaction in check.{{cite web|access-date=2014-01-01|title=Holmium acetate|url=http://www.metall.com.cn/hoac.htm}}
References
{{reflist}}
External reading
{{refbegin}}
- {{cite journal|title=Acetate Complexes of the Rare Earth and Several Transition Metal Ions|date=1962-05-01|doi=10.1021/ic50002a019|journal=Inorganic Chemistry|pages=293–296|volume=1|issue=2|issn=0020-1669|author=R. S. Kolat, J. E. Powell}}
{{refend}}
{{Holmium compounds}}
{{Acetates}}