Inorganic-organic hybridization induced uniaxial zero thermal expansion in MC 4 O 4 (M = Ba, Pb).

We report two inorganic-organic hybrid materials with pillar-layered architectures, BaC4O4 and PbC4O4, which show uniaxial zero thermal expansion (ZTE) along the hybrid direction over a wide temperature range. The local structure and lattice dynamic investigations reveal that the ZTE derives from the cooperation of the NTE of the inorganic Ba-O (or Pb-O) layer and the PTE of the squarate pillar.