Figure 2: The predicted crystal structures of stable Ca-C compounds.
From: Investigation of exotic stable calcium carbides using theory and experiment
(a) Thermodynamically stable Pnma structure of Ca2C. (b) The metastable low pressure P4/mbm structure of Ca3C2. (c) Thermodynamiclly stable high pressure C2/c structure of Ca3C2. (d) Thermodynamically stable P21/c structure of CaC. (e) Thermodynamically stable high pressure Imma structure of CaC. (f) Ca2C3 crystallizes in C2/m structure at pressures up to 28 GPa. (g) Thermodynamically metastable C2/c structure of Ca2C3. (h) Thermodynamically metastable P-1 structure of Ca2C3. (i) Thermodynamically metastable high pressure Imma of Ca2C3. (j) Thermodynamically stable P-1 structure of CaC2. (k) Thermodynamically stable Immm structure of CaC2. The blue and brown spheres represent calcium and carbon atoms, respectively.
