Tetrahedrally coordinated carbonates in Earth's lower mantle.

@article{Boulard2015TetrahedrallyCC,
  title={Tetrahedrally coordinated carbonates in Earth's lower mantle.},
  author={E. Boulard and Ding Pan and Giulia Galli and Zhenxian Liu and Wendy L. Mao},
  journal={Nature communications},
  year={2015},
  volume={6},
  pages={
          6311
        }
}
Carbonates are the main species that bring carbon deep into our planet through subduction. They are an important rock-forming mineral group, fundamentally distinct from silicates in the Earth's crust in that carbon binds to three oxygen atoms, while silicon is bonded to four oxygens. Here we present experimental evidence that under the sufficiently high pressures and high temperatures existing in the lower mantle, ferromagnesian carbonates transform to a phase with tetrahedrally coordinated… 
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