Protactinium(V) oxide

{{Chembox

| IUPACName = Protactinium(V) oxide

| ImageFile = Protactinium(V) oxide.jpg

| ImageName = Protactinium(V) oxide

|Section1={{Chembox Identifiers

| CASNo = 12036-75-8

| SMILES = O=[Pa](=O)O[Pa](=O)=O

| SMILES1 = O=[Pa]12O[Pa]3(=O)O[Pa](=O)(O1)O[Pa](=O)(O2)O3

| StdInChI = 1S/5O.2Pa

| InChI = 1S/10O.4Pa

| StdInChIKey = LDJMPPCAULZCAH-UHFFFAOYSA-N

| InChIKey = YHCILLCTPZINHI-UHFFFAOYSA-N

}}

|Section2={{Chembox Properties

| Formula={{Chem|Pa|2|O|5|}}

| MolarMass = 542.0688 g mol⁻¹

| Appearance = White, opaque crystals

}}

|Section3={{Chembox Structure

| CrystalStruct = cubic

| SpaceGroup = Fm-3m, No. 225}}

|Section4={{Chembox Hazards

| MainHazards = highly toxic, radioactive

| GHSPictograms = {{GHS06}}{{GHS08}}{{GHS09}}

| NFPA-H = 4

| NFPA-F = 0

| NFPA-R = 0

| NFPA-S = RA

}}

}}

Protactinium(V) oxide is a chemical compound with the formula Pa₂O₅. When it is reduced with hydrogen, it forms PaO₂. Aristid V. Grosse was first to prepare 2 mg of Pa₂O₅ in 1927.{{Cite web|url=http://www.3rd1000.com/elements/Protactinium.htm|title=Protactinium}} Pa₂O₅ does not dissolve in concentrated HNO₃, but dissolves in HF and in a HF + H₂SO₄ mixture and reacts at high temperatures with solid oxides of alkali metal and alkaline earth metals.{{cite journal | doi = 10.1021/ja01652a011 | year = 1954 | last1 = Sellers | first1 = Philip A. | last2 = Fried | first2 = Sherman | last3 = Elson | first3 = Robert E. | last4 = Zachariasen | first4 = W. H. | journal = Journal of the American Chemical Society | volume = 76 | issue = 23 | pages = 5935–5938 | title = The Preparation of Some Protactinium Compounds and the Metal| url = https://digital.library.unt.edu/ark:/67531/metadc172625/ }}Boris F. Myasoedov, H. W. Kirby, & Ivan G. Tananaev (2006) Protactinium, Chapter 4 in Morss, Lester R. & Edelstein, Norman M. & Fuger, Jean, (edit.) [http://radchem.nevada.edu/classes/rdch710/files/Protactinium.pdf The Chemistry of the Actinide and Transactinide Elements] {{Webarchive|url=https://web.archive.org/web/20170826210935/http://radchem.nevada.edu/classes/rdch710/files/Protactinium.pdf |date=2017-08-26 }} (PDF) (3. painos). Dordrecht: Springer. ss. 161–252.{{rp|195}}

As protactinium(V) oxide, like other protactinium compounds, is radioactive, toxic and very rare, it has very limited technological use. Mixed oxides of Nb, Mg, Ga and Mn, doped with 0.005–0.52% Pa₂O₅, have been

used as high temperature dielectrics (up to 1300 °C) for ceramic capacitors.{{rp|189}}