Solid phase
Official name
Tantalum
Secondary names
alpha-Tantalum; alpha-Ta
CAS number
7440-25-7
Type
Family
metallic solid
Class
true metal
Compound type
elemental solid
Chemical composition
Formula
$\alpha-Ta$
Chemical formula
Ta
Elemental formula
Ta
Isotope mixture type
terrestrial abundance
2.0
  Formula Name Family Number min-max Mole fraction Isotope mole fraction State Relevance
$Ta$ Tantalum element 1 1.0 1 constituent element main
Class
true metals (13)
Type
homovalent monolayer metals (13.01)
Phase name
$\alpha-Tantalum$
Phase type
crystalline
Crystal system
isometric (cubic)
Crystal class
hexoctahedral
Crystal class symbol
m-3m (Oh)
Crystal spacegroup
Im-3m
Molar mass
180.95 $g/mol$
Density
16.678 $g/cm^3$
State NTP
solid
Phase transitions
Phase transition type Other phases Temperature - Pressure
solid-liquid liquid Ta 3695°C (3968 K)
Phase transitions comments
a metastable beta-Ta phase can form as thin film and convert to beta-Ta above 750-775°C
Refringence type
isotropic
Pure color
gray blue
Diaphaneity
opaque
Luster
metallic
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