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Technical data for Rubidium

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Overview
NameRubidium
SymbolRb
Atomic Number37
Atomic Weight85.4678
Density1.532 g/cm3
Melting Point39.31 °C
Boiling Point688 °C

Thermal properties
PhaseSolid
Melting Point39.31 °C
Boiling Point688 °C
Absolute Melting Point312.46 K
Absolute Boiling Point961 K
Critical Pressure16 MPa (157.9 Atm)[note]
Critical Temperature2093 K[note]
Heat of Fusion2.19 kJ/mol
Heat of Vaporization72 kJ/mol
Heat of CombustionN/A
Specific Heat364 J/(kg K)[note]
Adiabatic IndexN/A
Neel PointN/A
Thermal Conductivity58 W/(m K)
Thermal ExpansionN/A

Bulk physical properties
Density1.532 g/cm3
Density (Liquid)1.46 g/cm3
Molar Volume0.000055788
Brinell Hardness0.216 MPa
Mohs Hardness0.3 MPa
Vickers HardnessN/A
Bulk Modulus2.5 GPa
Shear ModulusN/A
Young Modulus2.4 GPa
Poisson RatioN/A
Refractive IndexN/A
Speed of Sound1.3×103 m/s
Thermal Conductivity58 W/(m K)
Thermal ExpansionN/A

Reactivity
Valence1
Electronegativity0.82
ElectronAffinity46.9 kJ/mol
Ionization Energies
403, 2633, 3860, 5080, 6850, 8140, 9570, 13120, 1.45×104, 26740 kJ/mol

Health and Safety
Autoignition PointN/A
FlashpointN/A
Heat of CombustionN/A
DOT Hazard Class4.3
DOT Numbers1423
EU NumberN/A
NFPA Fire Rating3
NFPA Hazards
Water Reactive
NFPA Health Rating2
NFPA Reactivity RatingN/A
RTECS NumberRTECSVL8500000
NFPA LabelNFPA Label

Classifications
Alternate NamesNone
Names of AllotropesNone
Blocks
Group1
Period5
Electron Configuration[Kr]5s1
ColorSilver
Discovery
1861 in Germany
Gas phaseN/A
CAS NumberCAS7440-17-7
CID NumberCID5357696
Gmelin NumberN/A
NSC NumberN/A
RTECS NumberRTECSVL8500000

Electrical properties
Electrical TypeConductor
Electrical Conductivity8.3×106 S/m
Resistivity1.2×10-7 m Ω
Superconducting PointN/A

Magnetic properties
Magnetic TypeParamagnetic
Curie PointN/A
Mass Magnetic Susceptibility2.6×10-9
Molar Magnetic Susceptibility2.22×10-10
Volume Magnetic Susceptibility3.98×10-6

Abundances
% in Universe1×10-6%
% in Sun3×10-6%
% in Meteorites0.00032%
% in Earth's Crust0.006%
% in Oceans0.000012%
% in Humans0.00046%

Atomic dimensions and structure
Atomic Radius265 pm
Covalent Radius211 pm
Van der Waals RadiusN/A
Crystal StructureBody Centered Cubic
Lattice Angles
π/2, π/2, π/2
Lattice Constants
558.5, 558.5, 558.5 pm
Space Group NameIm_ 3m
Space Group Number229

Nuclear Properties
Half-LifeStable
LifetimeStable
Decay ModeN/A
Quantum Numbers2S1/2
Neutron Cross Section0.38
Neutron Mass Absorption0.0003
Known Isotopes
71Rb, 72Rb, 73Rb, 74Rb, 75Rb, 76Rb, 77Rb, 78Rb, 79Rb, 80Rb, 81Rb, 82Rb, 83Rb, 84Rb, 85Rb, 86Rb, 87Rb, 88Rb, 89Rb, 90Rb, 91Rb, 92Rb, 93Rb, 94Rb, 95Rb, 96Rb, 97Rb, 98Rb, 99Rb, 100Rb, 101Rb, 102Rb
Stable Isotopes
85Rb
Isotopic Abundances
85Rb72.17%
87Rb27.83%


Notes on the properties of Rubidium:

Critical Pressure: Value estimated based on extrapolation.

Critical Temperature: Value estimated based on extrapolation.

Specific Heat: Value given for solid phase.

Up to date, curated data provided by
Mathematica's ElementData function from Wolfram Research, Inc.

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