RADIUM, Ra (88)

Radium is almost colourless and readily combines with nitrogen on exposure to air, forming a black surface layer of radium nitride. All isotopes of radium are highly radioactive, with the most stable isotope being radium-226, which has a half-life of 1600 years and decays into radon gas and When it decays, ionising radiation is a product, which can excite fluorescent chemicals and cause radio-luminescence.

ELEMENT BRIEF

1898 by Pierre and Marie Curie, France.

DISCOVERY

Latin 'radius' meaning 'ray'.

ETYMOLOGY

Radium

ELEMENT

Ra

SYMBOL

88

ATOMIC NUMBER

7440-14-4

CAS NUMBER

ELEMENTAL SPECTRUM

Silver

ELEMENTAL COLOUR

-

REFRACTIVE INDEX

-

POISSON RATIO

44.604 cm³

MOLAR VOLUME

-

BRINELL HARDNESS

-

MOHS HARDNESS

-

VICKERS HARDNESS

-

SPEED OF SOUND

-

BULK MODULUS

-

SHEAR MODULUS

-

YOUNG MODULUS

ALLOTROPES

NONE

973.15 K, 700.00 °C

MELTING POINT

2,010.15 K, 1,737.00 °C

BOILING POINT

-

AUTOMATIC IGNITION

-

FLASHPOINT

-

CRITICAL TEMPERATURE

19.000'000 W/(m K)

CRITICAL PRESSURE

-

THERMAL CONDUCTIVITY

-

THERMAL EXPANSION

92.00 J/(kg K)

SPECIFIC HEAT

8.000 kJ/mol

HEAT FUSION

125.000 kJ/mol

HEAT VAPORISATION

-

HEAT COMBUSTION

-

CURIE POINT

-

NEEL POINT

-

ADIABATIC INDEX

Solid

PHASE

Conductor

ELECTRICAL TYPE

-

CONDUCTIVITY

1.00M S/m

RESISTIVITY

1.00μ Ω.m

SUPERCONDUCTING POINT

-

MAGNETIC TYPE

-

MASS SUSCEPTIBILITY

-

MOLAR SUSCEPTIBILITY

-

VOLUME SUSCEPTIBILITY

Alkaline Earth

CLASSIFICATION

223.018'502'3

ATOMIC WEIGHT

-

ATOMIC RADIUS

201 pm

COVALENT RADIUS SINGLE BOND

173 pm

COVALENT RADIUS DOUBLE BOND

159 pm

COVALENT RADIUS TRIPLE BOND

220 pm

VAN DER WAALS RADIUS

[Rn]7s²

ELECTRON CONFIGURATION

Cubic, Body-centred

CRYSTAL STRUCTURE

5.000'00 g/cm³

DENSITY AS SOLID

-

DENSITY AS LIQUID

-

DENSITY AS GAS

lm_3m

SPACE GROUP NAME

229

SPACE GROUP NUMBER

π/2, π/2 π/2

LATTICE ANGLES

514.8, 514.8 514.8 pm

LATTICE CONSTANTS

2

VALENCE

0.9

ELECTRONEGATIVITY

-

ELECTRON AFFINITY

IONISATION ENERGY