Main page (Russian) Search in database (English)

Properties of substance:

lanthanum

Group of substances:

inorganic

Physical appearance:

hexagonal metal

Empirical formula (Hill's system for organic substances):

La

Structural formula as text:

La

Molar/atomic mass: 138.91

Melting point (°C):

920

Boiling point (°C):

3950

Solubility (g/100 g of solvent):

gallium: 1 (500°C) [Ref.]
mercury: 0.0045 (0°C) [Ref.]
mercury: 0.0096 (25°C) [Ref.]
mercury: 0.0171 (50°C) [Ref.]
water: reaction [Ref.]

Numerical data:

Year of discovery: 1839
Superconducting temperature (K): 4.88 (α-form)
Superconducting temperature (K): 6 (β-form)

Density:

6.16 (20°C, g/cm3)

Reactions of synthesis:

  1. [Ref.1aster]
    LaCl3 + 3K → La + 3KCl
  2. [Ref.1aster]
    2LaCl3 → 2La + 3Cl2

Half-life:

11757La = 21.7 ms ()
117m57La = 10 ms ()
12057La = 2.8 s (β+ (100%), β+p (?))
12157La = 5.3 s (β+ (100%), β+p (?))
12257La = 8.6 s (β+ (100%), β+p (?))
12357La = 17 s (β+ (100%))
12457La = 29.21 s (β+ (100%))
124m57La = 21 s (β+ (100%))
12557La = 64.8 s (β+ (100%))
125m57La = 390 ms (internal transition (100%))
12657La = 54 s (β+ (100%))
126m57La = 20 s (β+ (100%))
12757La = 5.1 min (β+ (100%))
127m57La = 3.7 min (β+ (about 100%))
12857La = 5.18 min (β+ (100%))
12957La = 11.6 min (β+ (100%))
129m57La = 560 ms (internal transition (100%))
13057La = 8.7 min (β+ (100%))
130m57La = 760 ns (internal transition (100%))
130n57La = 33 ns (internal transition (100%))
13157La = 59 min (β+ (100%))
131m57La = 170 μs (internal transition (100%))
13257La = 4.8 h (β+ (100%))
132m57La = 24.3 min (internal transition (76%), β+ (24%))
13357La = 3.192 h (β+ (100%))
13457La = 6.45 min (β+ (100%))
134m57La = 29 μs (internal transition (100%))
13557La = 19.5 h (β+ (100%))
13657La = 9.87 min (β+ (100%))
136m57La = 114 ms (internal transition (100%))
13757La = 60 000 y (electron capture (100%))
137m57La = 342 ns (internal transition (100%))
13857La = 102 000 000 000 y (β+ (65.6%), β- (34.4%) (isotopic abundance 0,08881%))
138m57La = 116 ns (internal transition (100%))
138n57La = 2.0 μs (internal transition (100%))
13957La = stable ( (isotopic abundance 99,91119%))
139m57La = 315 ns (internal transition (100%))
14057La = 40.285 h (β- (100%))
14157La = 3.92 h (β- (100%))
14257La = 91.1 min (β- (100%))
142m57La = 870 ns (internal transition (100%))
14357La = 14.2 min (β- (100%))
14457La = 40.8 s (β- (100%))
14557La = 24.8 s (β- (100%))
14657La = 6.27 s (β- (100%))
146m57La = 10.0 s (β- (100%))
14757La = 4.06 s (β- (100%), β-n (0.041%))
14857La = 1.35 s (β- (100%), β-n (0.15%))
14957La = 1.07 s (β- (100%), β-n (1.43%))
15057La = 504 ms (β- (100%), β-n (2.7%))
15157La = 465 ms (β- (100%), β-n )
15257La = 287 ms (β- (100%), β-n)
15357La = 245 ms (β- (100%), β-n)
15457La = 161 ms (β- (100%), β-n)
15557La = 101 ms (β- (100%), β-n)
15657La = 84 ms (β- (100%), β-n)

Vapour pressure (Torr):

1 (2156°C)
10 (2474°C)
100 (2387°C)

Electrode potential:

La3+ + 3e- → La, E = -2.522 V (water, 25°C)

Standard molar enthalpy (heat) of formation ΔfH0 (298.15 K, kJ/mol):

0 (s)

Standard molar Gibbs energy of formation ΔfG0 (298.15 K, kJ/mol):

0 (s)

Standard molar entropy S0 (298.15 K, J/(mol·K)):

57.3 (s)

Molar heat capacity at constant pressure Cp (298.15 K, J/(mol·K)):

27.6 (s)

Molar enthalpy (heat) of fusion ΔfusH (kJ/mol):

6.7

Enthalpy (heat) of vaporization ΔvapH (kJ/mol):

413

Standard molar enthalpy (heat) of formation ΔfH0 (298.15 K, kJ/mol):

430 (g)

Standard molar entropy S0 (298.15 K, J/(mol·K)):

182.3 (g)

Molar heat capacity at constant pressure Cp (298.15 K, J/(mol·K)):

22.8 (g)

References:

  1. Seidell A. Solubilities of inorganic and metal organic compounds. - 3ed., vol.1. - New York: D. Van Nostrand Company, 1940. - pp. 887
  2. Гурвич Я.А. Справочник молодого аппаратчика-химика. - М.: Химия, 1991. - pp. 51 [Russian]
  3. Некрасов Б.В. Основы общей химии. - Т.2. - М.: Химия, 1973. - pp. 72-73 [Russian]
  4. Рабинович В.А., Хавин З.Я. Краткий химический справочник. - Л.: Химия, 1977. - pp. 75 [Russian]
  5. Справочник по растворимости. - Т.1, Кн.1. - М.-Л.: ИАН СССР, 1961. - pp. 595 [Russian]

    What information do you need?




    © Collected Ruslan Anatolievich Kiper, burewestnik@mail.ru