Re: [sdpd] structure of CrVO4

["Wilson Crichton" <crichton...@esrf.fr>]

Dear Hamid,

At ambient conditions CrVO4 has the NiSO4-type structure.

Frazer and Brown (1962) Physical Review vol 125 p1283, for example, have
investigated the (magnetic) structure of this phase and other vanadates and
anhydrous sulphates. Their findings are accordance with previous studies by
Brandt (1943) Arkiv Kemi Min Geol A 17, p 1 (CrVO4), Dimaras (1957) Acta
Cryst Vol 10 p 313 (NiSO4), Poljak (1958) vol 11 p 306 (NiSO4) and
Coing-Boyat (1959) vol 12 p 939 (FeSO4). If you can get any of these they
will do for initial model, the cell parameters you can get from the PDF. If
not:

In the orthorhombic space group Cmcm (a = 5.568 Å, 8.208 Å, c = 5.977 Å,
from F&B; a = 5.581 Å, b = 8.237 Å, c = 5.581 Å PDF 38-1376; NB I have
changed the cell from the Amam)

    Z = 4 with    Cr on     4a site at (0,0,0)
                        V           4c aite at (0, 0.353, 1/4)
                        O1         8f site at (0, 0.237, 0.010)
                        O2         8g site at (0.247, 0.490, 1/4)

Interestingly, at the same time as these studies were undertaken, the
structure of the high pressure form of these phases was determined, Young
and Schwartz (1962) Acta Cryst vol 15 p 1305 [PDF 15-0296] (see also
Dachille and Roy (1959) Z Krist 111 p 451), as being that of the rutile-type
structure; analogous to the ambient rutile-type CrTaO4 and CrNbO4 phases.

Best of luck,


Wilson Crichton



 

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