Table 1 Bader atomic charge Q, the degree of ionicity, and \(\rho _{{\mathrm{intra}}}/\rho _{{\mathrm{inter}}}\) of several AB2X2 compounds with the CaAl2Si2-type structure

From: Insights into the design of thermoelectric Mg3Sb2 and its analogs by combining theory and experiment

Compounds

\(\rho _{{\mathrm{intra}}}/\rho _{{\mathrm{inter}}}\)

Q (e)

Degree of ionicity (%)

A

B

X

A layer

B2X2 layer

Mg3Sb2

1.47

1.51

1.47

−2.23

75.5

73.9

Mg3Bi2

1.38

1.43

1.40

−2.11

71.5

70.2

CaMg2Sb2

1.39

1.39

1.48

−2.17

69.5

73.2

CaMg2Bi2

1.37

1.37

1.42

−2.10

68.5

70.5

CaZn2Sb2

2.34

1.37

0.31

−0.99

68.5

24.3

CaCd2Sb2

2.20

1.38

0.28

−0.97

69.0

23.2

  1. The data of Bader atomic charge and \(\rho _{{\mathrm{intra}}}/\rho _{{\mathrm{inter}}}\) are adapted from ref. 79. The degree of ionicity is estimated from the charge transfer index,99 which is calculated by the average of the atomic charge divided by the nominal oxidation charge of the atoms in unit cell. \(\rho _{{\mathrm{inter}}}\) denotes the electron density value at bond critical point (BCP) of the interlayer A-X bond, while \(\rho _{{\mathrm{intra}}}\) represents the average electron density value at BCPs of the two intralayer B-X bonds. The data of CaCd2Sb2 are calculated in this work using the previous computational methods79
Back to article page