User:Benjah-bmm27/Polonium dichloride

Polonium compounds, e.g. polonium dichloride, PoCl₂.

Holleman & Wiberg p. 594: ruby-red, m.p. 355 °C, subl. pt. 130 °C: http://books.google.com/books?id=Mtth5g59dEIC&lpg=RA1-PA1394&dq=isbn%3A0123526515&pg=RA1-PA594.

J. Chem. Soc. (1955) 2320-2326:

Preparation

Prepared by thermal decomp. of PoCl₄ at 300 °C, by reduction of cold, slightly moist PoCl₄ by SO₂, and by heating PoCl₄ in a stream of CO or H₂S at 150 °C.

Reactions

Dissolves in dil. HCl to give a pink soln. which autoxidises to Po(IV), and is immediately oxidised by H₂O₂ or Cl₂ water. Addition of KOH to the pink soln. gives dark brown ppt. - hydrated PoO or Po(OH)₂? Rapidly oxidised to Po(IV). With 0.1 N HNO₃, get dark red soln. then white flocculent ppt. of unknown comp.

Structure

Crystal structure: orthorhombic (space group P222 or Pmmm? paper and CIF disagree). Lattice parameters in Å: a = (3.66 ± 0.01), b = (4.34 ± 0.01), c = (4.49 ± 0.01). Calculated density 6.50 g/cm³. Distorted cubic (box 3.122 Å × 3.122 Å × 3.660 Å) coordination of Po as {PoCl₈}. Distorted square planar coordination of Cl as {ClPo₄} (Cl1 rectangle 4.430 Å × 3.660 Å, Cl2 rectangle 4.490 Å × 3.660 Å).