Eur. Phys. J. B 12, 497-508 (1999)
https://doi.org/10.1007/s100510051031

Structural investigation of a new variety of the low dimensional conductor (PO₂)₄(WO₃)₂₃ with 2m=5+5: P₄W₁₀O₃₈ ^*

¹ Laboratoire CRISMAT (CNRS UMR 6508) , ISMRA-Université de Caen, 14050 Caen Cedex, France
² Laboratoire de Physique des Solides (CNRS UMR 8502) , Université de Paris-Sud, 91405 Orsay Cedex, France
³ Département Sciences Physiques et Mathématiques, CNRS, 3 rue Michel-Ange, 75794 Paris Cedex 16, France

Received: 12 March 1999
Revised: 20 May 1999
Published online: 13 August 2012

Abstract

A new variety of , m = 5 member of the monophosphate tungsten-bronze family with pentagonal tunnels (), , has been isolated and studied by X-ray diffraction measurements. The structure has been solved by direct methods from single crystal X-ray data. The monoclinic unit cell corresponds to a regular stacking of -type slabs which are all five--octahedra thick and connected through tetrahedra. This structure is comparable to that previously described for the 'series with m = 4 () and m = 6 (). An X-ray diffuse scattering investigation has revealed that this member is subjected to charge density wave instabilities (CDW) located on chains running along the directions. Two CDW transitions have been observed at and , bearing some resemblance with those exhibited by the m = 4 member. The corresponding modulation wave vectors can be accounted for by a hidden nesting mechanism which connects the crossing points of differently oriented quasi-planar Fermi surfaces, as found for the low m (4 and 6) members of the MPTB's.