Perhaps one of the most studied materials to exhibit negative thermal expansion is zirconium tungstate (ZrW 2 O 8). This compound contracts continuously over a temperature range of 0.3 to 1050 K (at higher temperatures the material decomposes). Other materials that exhibit NTE behaviour include other members of the AM 2 O 8 family of materials (where A = Zr or Hf, M = Mo or W) and HfV 2 O 7 and ZrV 2 O 7, though HfV 2 O 7 and ZrV 2 O 7 only in their high temperature phase starting at 350 to 400 K. A 2 (MO 4) 3 also is an example of controllable negative thermal expansion. Cubic materials like ZrW 2 O 8 and also HfV 2 O 7 and ZrV 2 O 7 are especially precious for applications in engineering because they exhibit isotropic NTE i.e. the NTE is the same in all three dimensions making it easier to apply them as thermal expansion compensators.