Main page (Russian)
Search in database (English)
Sitemap (Russian)
New version database
Properties of substance:
niobium
Group of substances:
inorganic
Physical appearance:
cubic metal
Empirical formula (Hill's system for organic substances):
Nb
Structural formula as text:
Nb
Molar/atomic mass: 92.91
Melting point (°C):
2470
Boiling point (°C):
4760
Solubility (g/100 g of solvent):
lithium molten
: 0.0008 (700°C) [
Ref.
]
mercury
: insoluble [
Ref.
]
potassium fused
: 0.0001 (700°C) [
Ref.
]
sodium fused
: 0.0035 (700°C) [
Ref.
]
water
: insoluble [
Ref.
]
Numerical data:
Year of discovery: 1801
Superconducting temperature (K): 9.3
Density:
8.57 (20°C, g/cm
3
)
Vapour pressure (Torr):
0.1 (2980°C)
1 (3300°C)
10 (3780°C)
100 (4240°C)
Electrode potential:
Nb
3+
+ 3e
-
→ Nb, E = -1.1 V (water, 25°C)
Standard molar enthalpy (heat) of formation Δ
f
H
0
(298.15 K, kJ/mol):
0 (s)
Standard molar Gibbs energy of formation Δ
f
G
0
(298.15 K, kJ/mol):
0 (s)
Standard molar entropy S
0
(298.15 K, J/(mol·K)):
36.6 (s)
Molar heat capacity at constant pressure C
p
(298.15 K, J/(mol·K)):
24.6 (s)
Molar enthalpy (heat) of fusion Δ
fus
H (kJ/mol):
28
Enthalpy (heat) of vaporization Δ
vap
H (kJ/mol):
662
Standard molar enthalpy (heat) of formation Δ
f
H
0
(298.15 K, kJ/mol):
723 (g)
Standard molar entropy S
0
(298.15 K, J/(mol·K)):
186.2 (g)
Molar heat capacity at constant pressure C
p
(298.15 K, J/(mol·K)):
30.2 (g)
References:
Гибало И.М. Аналитическая химия ниобия и тантала. - М.: Наука, 1967. - pp. 14-15 [Russian]
Гурвич Я.А. Справочник молодого аппаратчика-химика. - М.: Химия, 1991. - pp. 51 [Russian]
Ниобий и тантал. - М.: Металлургия, 1990 [Russian]
Рабинович В.А., Хавин З.Я. Краткий химический справочник. - Л.: Химия, 1977. - pp. 88 [Russian]
Редкие и рассеянные элементы. Химия и технология. - Кн. 2. - М.: Мисис, 1998. - pp. 258-262 [Russian]
Химическая энциклопедия. - Т. 3. - М.: Советская энциклопедия, 1992. - pp. 249-251 [Russian]
What information do you need?
© Collected Ruslan Anatolievich Kiper, burewestnik@mail.ru