A Negative Thermal Expansion Material of ZrMgMo₃O₁₂

A material with the formula ZrMgMo₃O₁₂ having negative thermal expansion is presented and characterized. It is shown that ZrMgMo₃O₁₂ crystallizes in an orthorhombic symmetry with space group Pnma(62) or Pna2₁(33) and exhibits negative thermal expansion in a large temperature range (α_l=?3.8×10^?6 K^?1 from 300 K to 1000 K by x-ray diffraction and α_l =?3.73×10^?6 K^?1 from 295 K to 775 K by dilatometer). ZrMgMo₃O₁₂ remains the orthorhombic structure without phase transition or decomposition at least from 123 K to 1200 K and is not hygroscopic. These properties make it an excellent material with negative thermal expansion for a variety of applications.