iv : CHROMIUM DATA SHEET

ELEMENT NAME Chromium ORIGIN Chroma (Greek - colour)
ELEMENT TYPE 1st row Transition metal STRUCTURE Cubic body centred
DISCOVERED BY Louis Vauquelin LOCATION France
YEAR DISCOVERED 1797
ATOMIC NUMBER 24 ATOMIC WEIGHT 51.996
SHELLS 2,8,13,1 FILLING ORBITAL 3d5
MELTING POINT 1857 °C BOILING POINT 2672 °C
COVALENT RADIUS 1.18Å ATOMIC RADIUS 1.85Å
ATOMIC VOLUME 7.23cm3
ELECTRONEGATIVITY 1.66 OXIDATION STATES 6, 3, 2
1st IONISATION 6.766V 2nd IONISATION 16.50V
3rd IONISATION 30.96V
DENSITY (@ 293K) 7.19g cm-3 SPECIFIC HEAT 0.45 J g-1 K
HEAT VAPORISATION 344.30 kJ mol-1 HEAT OF FUSION 16.90 kJ mol-1
ELEC CONDUCTIVITY 0.0774x106 cm-1 W-1 THERMAL COND 0.937 W cm-1 K-1

SOURCES : Does not occur freely in nature. Chromite [Fe, Mg(CrO4)] is it's most important mineral.

USES : Used to make stainless steel. It gives colour to rubies and emeralds.

ELEMENT NUCLIDES :

Nuclide Abundance (%) Weight Spin Half life Decay modes
49Cr 0 49 2.5 42.3m b+
50Cr 4.31 49.946 0 Stable
51Cr 0 50.945 7 27.70 days g
52Cr 83.76 51.9405 0 Stable
53Cr 9.55 52.9407 1.5 Stable
54Cr 2.38 53.9389 0 Stable

Data taken from "Periodic Data Sheets" - A C3 computer program.


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