Crystal Structure and Spectroscopic Properties of Na2K6(VO)2(SO4)7
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- 作者：D. A. Karydis ; S. Boghosian ; K. Nielsen ; K. M. Eriksen ; and R. Fehrmann
- 刊名：Inorganic Chemistry
- 出版年：2002
- 出版时间：May 6, 2002
- 年：2002
- 卷：41
- 期：9
- 页码：2417 - 2421
- 全文大小：92K
- 年卷期：v.41,no.9(May 6, 2002)
- ISSN：1520-510X
文摘
Red-brown crystals of a new mixed alkali oxo sulfato vanadium(V) compound Na2K6(VO)2(SO4)7, suitable for X-raydetermination, have been obtained from the catalytically important binary molten salt system M2S2O7-V2O5 (M =80% K and 20% Na). By slow cooling of a mixture with the mole fraction XV2O5 = 0.24 from 325 
deg.gif">C, i.e., just belowthe liquidus temperature, to the solidus temperature of around 300 deg.gif">C, a dark reddish amorphous phase wasobtained containing crystals of the earlier described V(V)-V(IV) mixed valence compound K6(VO)4(SO4)8 and Na2K6(VO)2(SO4)7 described here. This compound crystallizes in the tetragonal space group P43212 (No. 96) with a =9.540(3) Å, c = 29.551(5) Å at 20 deg.gif">C and Z = 4. It contains a distorted VO6 octahedron with a short V-O bondof 1.552(6) Å, a long one of 2.276(5) Å trans to this, and four equatorial V-O bonds in the range 1.881(6)-1.960(6) Å. The deformation of the VO6 octahedron is less pronounced compared to that of the known oxo sulfato V(V)compounds. Each VO3+ group is coordinated to five sulfate groups of which two are unidentately coordinated andthree are bidentate bridging to neighboring VO3+ groups. The length of the S-O bonds in the S-O-V bridges ofthe two unidentately coordinated sulfato groups are 1.551(6) Å and 1.568(6) Å, respectively, which are unusuallylong compared to our earlier measurements of sulfate groups in other V(III), V(IV), and V(V) compounds.
deg.gif">C, i.e., just belowthe liquidus temperature, to the solidus temperature of around 300 deg.gif">C, a dark reddish amorphous phase wasobtained containing crystals of the earlier described V(V)-V(IV) mixed valence compound K6(VO)4(SO4)8 and Na2K6(VO)2(SO4)7 described here. This compound crystallizes in the tetragonal space group P43212 (No. 96) with a =9.540(3) Å, c = 29.551(5) Å at 20 deg.gif">C and Z = 4. It contains a distorted VO6 octahedron with a short V-O bondof 1.552(6) Å, a long one of 2.276(5) Å trans to this, and four equatorial V-O bonds in the range 1.881(6)-1.960(6) Å. The deformation of the VO6 octahedron is less pronounced compared to that of the known oxo sulfato V(V)compounds. Each VO3+ group is coordinated to five sulfate groups of which two are unidentately coordinated andthree are bidentate bridging to neighboring VO3+ groups. The length of the S-O bonds in the S-O-V bridges ofthe two unidentately coordinated sulfato groups are 1.551(6) Å and 1.568(6) Å, respectively, which are unusuallylong compared to our earlier measurements of sulfate groups in other V(III), V(IV), and V(V) compounds.