Crystalline forms of elements

Three forms are listed: room temperature form, at 0K (T1 is the lowest transition temperature), and before melting (Tm is the melting temperature). Also the number, n, of different crystalline forms at atmospheric pressure is given.

Temperature is in K, radius is in A. RA is atomic radius, RV1 is (sqrt(2)V1)^(1/3)/2, where V1 is the volume per atom. Note that fcc2 = fcc lattice of diatomic molecules, dsc = deformed sc lattice, chh = close-packed chh stacking etc.

  RA at300 RV1 n < T1 < Tm
H 0.79 gas 1 hcp hcp 14 hcp: a=3.119, c=5.086
He 0.49 gas 0 liq 4.2 hcp at high pressure
Li 2.05 bcc 1.56 2 chh 78 bcc 454
Be 1.40 hcp 1.13 2 hcp 1527 bcc 1558
B 1.17   3 hR105 2346 see details
C 0.91 gra 1 gra gra 4500 see details, Tm is sublimation, for dia RV1=1.00
N 0.75 gas 2 fcc2 36 hcp2 63 see also gamma-N (fct2)
O 0.65 gas 3 hcp2 24 cP16 55 fcc2 (T<44)
F 0.57 gas 2 fco2 46 cP16 53 cP16 (beta-F)
Ne 0.51 gas 1 fcc fcc 24
Na 2.23 bcc 1.91 1 chh 35 bcc 371
Mg 1.72 hcp 1.60 1 hcp hcp 922
Al 1.82 fcc 1.43 1 fcc fcc 933
Si 1.46 dia 1.52 1 dia dia 1690
P 1.23 oC8 1 oC8 oC8 1300 see details
S 1.09 oF ?   386
Cl 0.97 gas 1 hal hal 172
Ar 0.88 gas 1 fcc fcc 20
K 2.77 bcc 2.34 1 bcc bcc 337
Ca 2.23 fcc 1.97 2 fcc 716 bcc 1120
Sc 2.09 hcp 1.64 2 hcp 1607 bcc 1812
Ti 2.00 hcp 1.46 2 hcp 1156 bcc 1941
V 1.92 bcc 1.35 1 bcc bcc 2192
Cr 1.85 bcc 1.29 1 bcc bcc 2176
Mn 1.79 cI58 4 cI58 1000 bcc 1517 cP20 (T<1370), fcc (T<1410)
Fe 1.72 bcc 1.28 4 bcc 1180 bcc 1810 fcc (T<1700), Tc=1042
Co 1.67 hcp 1.25 2 hcp 700 fcc 1768
Ni 1.62 fcc 1.25 1 fcc fcc 1728
Cu 1.57 fcc 1.28 1 fcc fcc 1356
Zn 1.53 hcp 1.39 1 hcp hcp 693
Ga 1.81 oC8 1 oC8 oC8 303
Ge 1.52 dia 1.59 1 1211
As 1.33 hR2 1.56 ?   1090
Se 1.22 hP3 ? hP3 490
Br 1.12 liq 1 hal hal 267
Kr 1.03 gas 1 fcc fcc 89
Rb 2.98 bcc 2.54 1 bcc bcc 312
Sr 2.45 fcc 2.15 3 fcc 488 bcc 1043 h (T<878)
Y 2.27 hcp 1.80 2 hcp 1758 bcc 1801
Zr 2.16 hcp 1.60 2 hcp 1135 bcc 2125
Nb 2.08 bcc 1.47 1 bcc bcc 2741
Mo 2.01 bcc 1.40 1 bcc bcc 2895
Tc 1.95 hcp 1.36 1 hcp hcp 2487
Ru 1.89 hcp 1.34 1 hcp hcp 2600
Rh 1.83 fcc 1.34 1 fcc fcc 2235
Pd 1.79 fcc 1.38 1 fcc fcc 1825
Ag 1.75 fcc 1.44 1 fcc fcc 1234
Cd 1.71 hcp 1.56 1 hcp hcp 594
In 2.00 fct 1.67 1 fct fct 430
Sn 1.72 tI4 2 dia 286 tI4 505
Sb 1.53 hR2 1.75 1 hR2 hR2 903
Te 1.42 hP3 1 hP3 hP3 723
I 1.32 hal 1 hal hal 386
Xe 1.24 gas 1 fcc fcc 161
Cs 3.34 bcc 2.74 1 bcc bcc 302
Ba 2.78 bcc 2.24 1 bcc bcc 995
La 2.74 ch 1.88 3 ch 533 bcc 1193 fcc (T<1153)
Ce 2.70 fcc 1.82 4 fcc 80 bcc 1071 h (T<260), fcc (T<998)
Pr 2.67 hP4 1.83 2 hP4 1070 bcc 1204
Nd 2.64 hP4 1.82 2 hP4 1130 bcc 1291
Pm 2.62 hP4 1.81 ? hP4   1400
Sm 2.59 chh 1.80 2 chh 1190 bcc 1345
Eu 2.56 bcc 2.04 1 bcc bcc 1099
Gd 2.54 hcp 1.80 2 hcp 1535 bcc 1585
Tb 2.51 hcp 1.78 2 hcp 1570 bcc 1630
Dy 2.49 hcp 1.77 2 hcp 1660 bcc 1680
Ho 2.47 hcp 1.77 2 hcp 1710 bcc 1740
Er 2.45 hcp 1.76 2 hcp 1700 bcc 1800
Tm 2.42 hcp 1.75 2 hcp 1793 bcc 1818
Yb 2.40 fcc 1.94 2 hcp 1069 bcc 1094
Lu 2.25 hcp 1.73 ? hcp   1936
Hf 2.16 hcp 1.58 2 hcp 2013 bcc 2500
Ta 2.09 bcc 1.47 1 bcc bcc 3269
W 2.02 bcc 1.41 1 bcc bcc 3693
Re 1.97 hcp 1.38 1 hcp hcp 3450
Os 1.92 hcp 1.35 1 hcp hcp 3320
Ir 1.87 fcc 1.36 1 fcc fcc 2720
Pt 1.83 fcc 1.39 1 fcc fcc 2042
Au 1.79 fcc 1.44 1 fcc fcc 1337
Hg 1.76 liq 1 dfcc dfcc 234 dfcc (P>12 kbar), bct (37), oR (120), hcp (370)
Tl 2.08 hcp   bcc  
Pb 1.81 fcc 1.75 1 fcc fcc 600
Bi 1.63 hR2 1.84 1 dsc dsc 544
Po 1.53 sc 2 sc 327 dsc 527
At 1.43         radioactive
Rn 1.34 gas 1 fcc fcc 223