Scandium

Calcium - Scandium - Titanium
Sc Y
	Full table

General

Name, Symbol, Number

Scandium, Sc, 21

Chemical series

Transition metals

Group, Period, Block

3, 4 , d

Density, Hardness

2985 kg/m³, U/K

Appearance

Silvery white

Atomic Properties

Atomic weight

44.955910 amu

Atomic radius (calc.)

160 (184) pm

Covalent radius

144 pm

van der Waals radius

no data

Electron configuration

[Ar]3d3d¹ 4s²

e^- 's per energy level

2, 8, 9, 2

Oxidation states (Oxide)

3 (weak base)

Crystal structure

Hexagonal

Physical Properties

State of matter

Solid (__)

Melting point

1814 K (2806 �F)

Boiling point

3103 K (5126 �F)

Molar volume

15.00 ×1010^-3 m³/mol

Heat of vaporization

314.2 kJ/mol

Heat of fusion

14.1 kJ/mol

Vapor pressure

22.1 Pa at 1812 K

Speed of sound

no data m/s at 293.15 K

Miscellaneous

Electronegativity

1.36 (Pauling scale)

Specific heat capacity

568 J/(kg*K)

Electrical conductivity

1.77 10⁶/m ohm

Thermal conductivity

15.8 W/(m*K)

1^st ionization potential

633.1 kJ/mol

2^nd ionization potential

1235.0 kJ/mol

3^rd ionization potential

2388.6 kJ/mol

4^th ionization potential

7090.6 kJ/mol

5^th ionization potential

8843 kJ/mol

6^th ionization potential

10679 kJ/mol

7^th ionization potential

13310 kJ/mol

8^th ionization potential

15250 kJ/mol

9^th ionization potential

17370 kJ/mol

10^th ionization potential

21726 kJ/mol

Most Stable Isotopes

iso	NA	half-life	DM	DE M eV	DP
⁴⁵Sc	100%	Sc is stable with 24 neutrons
⁴⁶Sc	{syn.}	83.79 dayss	β^-	2.367	⁴⁶Ti

SI units & STP are used except where noted.

Scandium is a chemical element in the periodic table that has the symbol Sc and atomic number 21. A soft, silvery, white transition element, scandium occurs in rare minerals from Scandinavia and is is sometimes classified along with yttrium and the lanthanides as a rare earth.

Notable Characteristics

Scandium is a rare, soft, silvery, trivalent, very light metallic element that develops a slightly yellowish or pinkish cast when exposed to air. This element resembles yttrium and rare earth metals more than it resembles aluminum or titanium (which are closer on the periodic table). The most common oxidation state of scandium is +3 and this metal is not attacked by a 1:1 mixture of HNO₃ and 48% HF.

Applications

Approximately 20 kg of scandium (as Sc₂ O₃) are used annually in the United States to make high-intensity lights. The radioactive isotope Sc-46 is used in oil refinery crackers as a tracing agent. When scandium iodide is added to mercury vapor lamps a highly efficient artificial sunlight-like light source is produced which is used in indoor or night-time color televisions. Scandium also has a much higher melting point than aluminum, and has been studied for possible use in spacecrafts.

History

Scandium (Latin Scandia meaning "Scandinavia") was discovered by Lars Fredrick Nilson in 1879 while he and his team were looking for rare earth metals. Nilson used spectrum analysis to find the new element within the minerals euxenite and gadolinite. To isolate the element he processed 10 kilograms of euxenite with other rare-earth residues to obtain about 2 gramss of very pure scandium oxide (Sc₂O₃).

Dmitri Mendeleev, in 1869, predicted the existence and some properties of this element, which he called ekaboron, using his periodic law. Per Theodor Cleve discovered scandium oxide at about the same time as Nilson but unlike Nilson, Cleve determined that scandium was identical to ekaboron.

In 1937 metallic scandium was prepared for the first time by electrolysis of a eutectic melt of potassium, lithium, and scandium chlorides at 700 to 800° C. Tungsten wire in a pool of liquid zinc were the electrodes in a graphite crucible. The first pound of 99% pure scandium metal wasn't produced until 1960.

Occurrence

Rare minerals from Scandinavia and Malagasy such as thortveitite, euxenite and gadolinite are the only known concentrated sources of this element (which is never found as a free metal).

Element 21 is the 23rd most abundant element in the sun and similar stars but on earth it is only the 50th most abundant element. Scandium is distributed widely on earth, occurring in trace quantities in over 800 minerals. The blue color of the aquamarine variety of beryl is thought to be caused by scandium. It is an important part of the rare mineral thortveitite and is found in residues that remain after tungsten is extracted from Zinnwald wolframite.

Thortveitite is the primary source of scandium with uranium mill tailings by-products also being an important source. Pure scandium is commercially produced by reducing scandium fluoride with calcium metal.

Isotopes

Naturally occurring scandium is composed of 1 stable isotope Sc-45. 13 radioisotopes have been characterized with the most stable being Sc-46 with a half-life of 83.79 days, Sc-47 with a half-life of 3.3492 days, and Sc-48 with a half-life of 43.67 hours. All of the remaining radioactive isotopes have half-lifes that are less than 4 hours and the majority of these have half lifes that are less than 2 minutes. This element also has 5 meta states with the most stable being Scm-44 (t_� 58.6 h).

The isotopes of scandium range in atomic weight from 39.978 amu (Sc-40) to 53.963 amu (Sc-54). The primary decay mode before the only stable isotope, Sc-45, is electron capture and the primary mode after is beta emission. The primary decay products before Sc-45 are element 20 (calcium) isotopes and the primary products after are element 22 (titanium) isotopes.

Precautions

Scandium metal powder is combustible and presents a fire hazard.