First-principle studies of Ca–X (X=Si,Ge,Sn,Pb) intermetallic compounds

Effect of Na Addition on Electric Properties of Ca2Si Sintered Compacts

“…Ca 2 Si is predicted to have a direct band gap of 0.362 eV [1], 0.35 eV [2], 0.31 eV [10], 0.30 eV [16] and 0.324 eV [17]. The measured E A of 0.13 eV for Ca 2 Si is about a half the calculated electronic band gap mentioned above.…”

Mechanism of Pb Removal from Brass Scrap by Compound Separation Using Ca and NaF

“…In the molten brass at 1223 K, Ca 2 Pb and CaF 2 are solid because the melting points of Ca 2 Pb and CaF 2 are 1469 and 1691 K, respectively [14]. The melting point of NaF is 1266 K. Therefore, NaF is present in solid form.…”

Thermodynamic Properties of Alloys in the Binary Ca–Ge System

“…and calorimetry methods by Notin and Mejbar et al [1,2] They were also estimated in terms of the semiempirical Miedema model, calculated from first principles (Yang et al [3] ), and assessed through simultaneous optimization with the data for phase equilibria by Djaballah et al [4] Notin et al [1] stated that they measured DH(0.6 < x Ge < 1) using the calorimetry method, though the experimental details were not given. The region 0 < x Ge < 0.2 should be noticed especially, because the calculation [1] resulted in positive enthalpies of mixing there.…”

“…However, the first-principles calculation by Bouderba et al [14] gave a conclusion that it is a-CaGe 2 that is thermodynamically stable at T > 155 K. The calculated thermodynamic properties of solid CaGe and CaGe 2 in [14] are consistent with the earlier results. [1][2][3][4] Additionally, Bouderba et al [14] suggested the existence of a new compound Ca 3 Ge 4 , which may be stable only at high temperatures close to the liquidus. Clearly, the temperature ranges of stability of these modifications require further study.…”