
The Elements 1.5 Data 95
Table 2.1-14B(a) Elements of Group IVB (CAS notation), or Group 4 (new IUPAC notation). Crystallographic properties
(see Table 2.1-14C for allotropic and high-pressure modifications)
Element name Titanium Zirconium Hafnium Rutherfordium
Chemical symbol Ti Zr Hf Rf
Atomic number Z 22 40 72 104
Units Remarks
Modification α-Ti α-Zr α-Hf
Crystal system, Bravais lattice hex hex hex
Structure type Mg Mg Mg
Lattice constant a 295.03 323.17 319.46 pm
Lattice constant c 468.36 514.76 505.11 pm
Space group P6
3
/mmc P6
3
/mmc P6
3
/mmc
Schoenflies symbol D
4
6h
D
4
6h
D
4
6h
Strukturbericht type A3 A3 A3
Pearson symbol hP2 hP2 hP2
Number A of atoms per cell 2 2 2
Coordination number 12 6 +6 12
Shortest interatomic distance, solid 291 318 pm
Table 2.1-14B(b) Elements of Group IVB (CAS notation), or Group 4 (new IUPAC notation). Mechanical properties
Element name Titanium Zirconium Hafnium Rutherfordium
Chemical symbol Ti Zr Hf Rf
Atomic number Z 22 40 72 104
Units Remarks
Density , solid 4.50 6.49 13.10 g/cm
3
Density , liquid 4.110 5.80 12.00 g/cm
3
Molar volume V
mol
10.55 14.02 13.41 cm
3
/mol
Surface tension, liquid 1.65 1.48 1.63 N/m Near T
m
Temperature coefficient 0.26 ×10
−3
−0.2×10
−3
−0.21×10
−3
N/(mK)
Coefficient of linear 8.35 × 10
−6
5.78× 10
−6
5.9×10
−6
1/K
thermal expansion α
Sound velocity, solid, transverse 2920 1950 2000 m/s
Sound velocity, 6260 4360 3671 m/s
solid, longitudinal
Compressibility κ 0.779× 10
−5
1.08× 10
−5
0.80× 10
−5
1/MPa Volume
compressibility
Elastic modulus E 102 68.0 138 GPa
Shear modulus G 37.3 24.8 53.0 GPa
Poisson number µ 0.35 0.37 0.29
Elastic compliance s
11
9.69 10.1 7.16 1/TPa
Elastic compliance s
33
6.86 8.0 6.13 1/TPa
Elastic compliance s
44
21.5 30.1 18.0 1/TPa
Elastic compliance s
12
−4.71 −4.0 −2.48 1/TPa
Elastic compliance s
13
−1.82 −2.4 −1.57 1/TPa
Elastic stiffness c
11
160 144 181 GPa
Elastic stiffness c
33
181 166 197 GPa
Elastic stiffness c
44
46.5 33.4 55.7 GPa
Elastic stiffness c
12
90 74 77 GPa
Elastic stiffness c
13
66 67 66 GPa
Tensile strength 235 150–450 400 MPa
Vickers hardness 2000–3500 903 1760
Part 2 1.5