- Cobalt compounds have been used to color glass and ceramics for millennia, dating back to ancient Egypt and China. - Swedish chemist Georg Brandt discovered cobalt as a new element in 1735 and showed that cobalt compounds were responsible for the blue color in glass. - Cobalt occurs naturally in combination with other elements like sulfur and arsenic in minerals, but is most often obtained as a byproduct of copper and nickel mining.

2. History
 Cobalt compounds have been used for centuries to impart
a rich blue color to glass, glazes and ceramics. Cobalt
has been detected in Egyptian sculpture and Persian
jewelry from the third millennium BC, in the ruins
of Pompeii (destroyed in 79 AD), and in China dating from
the Tang dynasty (618–907 AD) and the Ming
dynasty (1368–1644 AD).
 Cobalt has been used to color glass since the Bronze
Age. The excavation of the Uluburun shipwreck yielded an
ingot of blue glass, which was cast during the 14th
century BC. Blue glass items from Egypt are colored with
copper, iron, or cobalt. The oldest cobalt-colored glass
was from the time of the Eighteenth
dynasty in Egypt (1550–1292 BC). The location where the
cobalt compounds were obtained is unknown.

3. History
 Swedish chemist Georg Brandt (1694–
1768) is credited with discovering cobalt
circa 1735, showing it to be a new
previously unknown element different from
bismuth and other traditional metals, and
calling it a new "semi-metal.He was able to
show that compounds of cobalt metal were
the source of the blue color in glass, which
previously had been attributed to
the bismuth found with cobalt. Cobalt
became the first metal to be discovered
since the pre-historical period, during which
all the known metals (iron, copper, silver,
gold, zinc, mercury, tin, lead and bismuth)
had no recorded discoverers.

4. source
 The stable form of cobalt is created
in supernovas via the r-process.It
comprises 0.0029% of the Earth's crust and is
one of the first transition metals.
 Free cobalt (the native metal) is not found in
on Earth due to the amount of oxygen in the
atmosphere and chlorine in the ocean. Though
the element is of medium abundance, natural
compounds of cobalt are numerous. Small
amounts of cobalt compounds are found in
most rocks, soil, plants, and animals.

5. Source
 Cobalt in compound form occurs as a minor
component of copper and nickel minerals. It is
the major metallic component in combination
with sulfur and arsenic in the sulfidiccobaltite
(CoAsS), safflorite (CoAs2), glaucodot ((Co,Fe)
AsS), and skutterudite (CoAs3) minerals. The
mineral cattierite is similar to pyrite and occurs
together with vaesite in the copper deposits of
the Katanga Province. Upon contact with the
atmosphere, weathering occurs and the sulfide
minerals oxidize to form pink erythrite ("cobalt
glance":Co3(AsO4)2·8H2O)and spherocobaltite
(CoCO3).

6. How to get
 The main ores of cobalt are cobaltite, erythrite,
glaucodot and skutterudite (see above), but
most cobalt is obtained not by active mining of
cobalt ores, but rather by reducing cobalt
compounds that occur as by-products of nickel
and copper mining activities.
 Several methods exist for the separation of
cobalt from copper and nickel. They depend
on the concentration of cobalt and the exact
composition of the used ore. One separation
step involves froth flotation, in which
surfactants bind to different ore components,
leading to an enrichment of cobalt ores.

7. How to get
 Subsequent roasting converts the ores to
the cobalt sulfate, whereas the copper and the
iron are oxidized to the oxide.
The leaching with water extracts the sulfate
together with the arsenates. The residues are
further leached with sulfuric acid yielding a
solution of copper sulfate. Cobalt can also be
leached from the slag of the copper smelter.
 The products of the above-mentioned
processes are transformed into the cobalt
oxide (Co3O4). This oxide is reduced to the
metal by the aluminothermic reaction or
reduction with carbon in a blast furnace.

8. properties
 Color metallic gray
 Phase solid
 Melting point 1768 K
 Boiling point 3200 K
 Density (near r.t.) 8.90 g·cm−3
 Liquid density at m.p. 8.86 g·cm−3
 Heat of fusion 16.06 kJ·mol−1
 Heat of vaporization 377 kJ·mol−1
 Molar heat capacity 24.81 J·mol−1·K−1

9. compound
 Green cobalt(II) oxide (CoO)
 the black cobalt(II) sulfides, CoS2
 cobalt(III) sulfide (Co2S3).
 cobalt(II) fluoride (CoF2, pink),
 cobalt(II) chloride(CoCl2, blue),
 cobalt(II) bromide (CoBr2, green),
 cobalt(II) iodide (CoI2, blue-black)

10. Compund
 tris(triphenylphosphine)cobalt(I) chloride
((P(C6H5)3)3CoCl)
 caesium hexafluorocobaltate (Cs2CoF6)
 potassium percobaltate (K3CoO4).
 [Co(NH3)6]Cl3 cobalt(III) hexammine
chloride
 Cobalt carbonyl (Co2(CO)8)

11. Reaction
 With acids :
 CoO + 2 HX → CoX2 + H2O
 With water :
 CoCl2 + H2O → CoO + H2 + Cl2
 with base :
 CoX + 2 KOH → Co(OH)2 + K2X
 With oxygen :
 6 CoO + O 2 → 2 Co3O4

12. application
alloys
colouring
bateries
catalist radioisotop

14. History
 there are Chinese manuscripts suggesting
that "white copper" (cupronickel, known
as baitong) was used there between 1700
and 1400 BC. This Paktong white copper
was exported to Britain as early as the
17th century, but the nickel content of this
alloy was not discovered until 1822.
 In 1751, Baron Axel Fredrik Cronstedt was
trying to extract copper from kupfernickel—
and instead produced a white metal that he
named after the spirit that had given its
name to the mineral, nickel. In modern
German, Kupfernickel or Kupfer-Nickel
designates the alloy cupronickel.

15. Source
 On Earth, nickel occurs most often in combination with sulfur and iron
in pentlandite, with sulfur in millerite, with arsenic in the
mineral nickeline, and with arsenic and sulfur in nickel galena.Nickel is
commonly found in iron meteorites as the alloys kamacite and taenite.
 Australia and New Caledonia have the biggest estimate reserves (45%
all together).
 In terms of World Resources, identified land-based resources
averaging 1% nickel or greater contain at least 130 million tons of
nickel (about the double of known reserves). About 60% is
in laterites and 40% is in sulfide deposits.
 Based on geophysical evidence, most of the nickel on Earth is
postulated to be concentrated in the Earth's outer and inner
cores.Kamacite and taenite are naturally occurring alloys of iron and
nickel. For kamacite, the alloy is usually in the proportion of 90:10 to
95:5, although impurities (such as cobalt or carbon) may be present,
while for taenite the nickel content is between 20% and 65%. Kamacite
and taenite occur in nickel iron meteorites.

16. How to get
 Purification of nickel oxides to obtain the purest
metal is performed via the Mond process, which
increases the nickel concentrate to greater than
99.99% purity. This process was patented by Ludwig
Mond and has been in industrial use since before the
beginning of the 20th century. In the process, nickel
is reacted with carbon monoxide at around 40–80 °C
to form nickel carbonyl in the presence of a sulfur
catalyst. Iron gives iron pentacarbonyl, too, but this
reaction is slow. If necessary, the nickel may be
separated by distillation. Dicobalt octacarbonyl is
also formed in nickel distillation as a by-product, but
it decomposes to tetracobalt dodecacarbonyl at the
reaction temperature to give a non-volatile solid.

17. How to get
 Nickel is re-obtained from the nickel carbonyl by one
of two processes. It may be passed through a large
chamber at high temperatures in which tens of
thousands of nickel spheres, called pellets, are
constantly stirred. It then decomposes, depositing
pure nickel onto the nickel spheres. Alternatively, the
nickel carbonyl may be decomposed in a smaller
chamber at 230 °C to create a fine nickel powder.
The resultant carbon monoxide is re-circulated and
reused through the process. The highly pure nickel
produced by this process is known as "carbonyl
nickel".

18. Properties
 Phase solid
 Melting point 1728 K
 Boiling point 3003 K
 Density (near r.t.) 8.908 g·cm−3
 Liquid density at m.p. 7 81 g·cm−3
 Heat of fusion 17.48 kJ·mol−1
 Heat of vaporization 379 kJ·mol−1
 Molar heat capacity 26.07 J·mol−1·K−1

19. Compound
 Tetracarbonylnickel (Ni(CO)4)
 Bis(triphenylphosphine)nickel(II)
chloride NiCl2[P(C6H5)3]2
 K4[Ni2(CN)6] and K2[Ni2(CN)6]
 Nickel aquo complex [Ni(H2O)6]2+

20. Compound
Color of various Ni(II) complexes in aqueous solution. From left
to right, [Ni(NH3)6]2+, [Ni(C2H4(NH2)2)]2+, [NiCl4]2−, and
[Ni(H2O)6]2+

21. Reaction
 Reaction with oxygen
2Ni + O2 → 2NiO
 react with halides
Ni + Cl2 → NiCl2
 react with H2O
Ni + H2O → NiO + H2
 react with acid
Ni + HNO3 → Ni(NO3)2 + NO + H2O

22. Application
 The fraction of global nickel production
presently used for various applications is
as follows: 46% for making nickel steels;
34%innonferrous alloys and superalloys;
14% electroplating, and 6% into other
uses (catalyst, batteries, magnet, etc)