Citation: Grey, I.E.; Roth, R.S.; Li, C.; Mumme, W.G.; Planes, J.; Bendersky, L.A.; Chenavas, J. (2001). Characterization of new 5M and 7M polytypes of niobia-doped Ca2 Ta2O7. Journal of Solid State Chemistry, 161, pp. 274-287.
Formula: Ca2 Nb0.2 O7 Ta1.8
Chemical name: Ca2 (Ta1.8 Nb0.2) O7
List type: noninterleaving
List: 3D
Basis: (1;0;0 0;1;0 0;0;1)
Dimensionality: 3
Formula: Nb40 O140 Ta40 (Nb2 O7 Ta2)
Multiplicity: 1