Solid phase
Official name
beta Tantalum(V) oxide
Secondary names
Ditantalum pentaoxide; Tantalum pentoxide; beta Tantalum pentoxide; beta-Ta2O5
CAS number
1314-61-0
Type
Family
covalent network solid
Class
pseudometal (semi-conductor)
Compound type
oxide
Chemical composition
Formula
$\beta - Ta_2O_5$
Chemical formula
Ta2O5
Elemental formula
Ta2 O5
Isotope mixture type
terrestrial abundance
14.0
  Formula Name Family Number min-max Mole fraction Isotope mole fraction State Relevance
$Ta$ Tantalum element 2 0.2857142857142857 1 constituent element main
$O$ Oxygen element 5 0.7142857142857143 1 constituent element main
Oxides
Formula $Ta_{2}O_{5}$
Mass fraction (%) 100.0
Class
pseudometals (14)
Type
homovalent bilayer pseudometals (14.02)
Phase name
L- or $\beta-Ta_2O_5$
Phase type
crystalline
Crystal system
orthorhombic
Crystal class
pyramidal
Crystal class symbol
mm2 (C2v)
Crystal spacegroup
Pmm2
Molar mass
441.893 $g/mol$
Density
8.18 $g/cm^3$
State NTP
solid
Phase transitions
Phase transition type Other phases Temperature - Pressure
solid-liquid liquid Ta2O5 1872°C (2145 K)
solid-solid H- or alpha-Ta2O5 1000 - 1360°C (1270 - 1630 K)
Refringence type
biaxial
Refraction index $n_{\alpha}$
2.275
Pure color
colorless
Color
colorless, white
Diaphaneity
transparent to translucent
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