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Abundance of Group 12 elements.
Element Terrestrial abundance (ppm)
Zn 75 (Earth’s crust), 64 (soil), 30 x 10 -6 (sea water)
Cd 0.1 (Earth’s crust), 1 (soil), 1 x 10 -6 (sea water)
Hg 50 x 10 -6 (Earth’s crust), 2 x 10 -8 (soil), 40 x 10 -12 (sea water)


The naturally abundant isotopes of the Group 12 metals are listed in [link] .

Abundance of the major (non-synthetic) isotopes of the Group 12 metals. Isotopes labeled with * are radioactive.
Isotope Natural abundance (%)
Zinc-64 48.6
Zinc-66 27.9
Zinc-67 4.1
Zinc-68 18.8
Zinc-70 0.6
Cadmium-106 * 1.25
Cadmium-108 * 0.89
Cadmium-110 12.49
Cadmium-111 12.8
Cadmium-112 24.13
Cadmium-113 * 12.22
Cadmium-114 * 28.73
Cadmium-116 * 7.49
Mercury-196 0.15
Mercury-198 9.97
Mercury-199 16.87
Mercury-200 23.1
Mercury-201 13.18
Mercury-202 29.86
Mercury-204 6.87

Many radioisotopes of zinc have been characterized. Zinc-65 that has a half-life of 244 days, is the most long-lived isotope, followed by 72 Zn with a half-life of 46.5 hours. The most common decay mode of an isotope of zinc with a mass number lower than 64 is electron capture, producing an isotope of copper, [link] .

The most common decay mode of an isotope of zinc with mass number higher than 64 is beta decay (β–), which produces an isotope of gallium, [link] .

Naturally occurring cadmium is composed of 8 isotopes. For two of them, natural radioactivity was observed, and three others are predicted to be radioactive but their decay is not observed, due to extremely long half-life times. The two natural radioactive isotopes are 113 Cd (half-life = 7.7 x 10 15 years) and 116 Cd (half-life = 2.9 x 10 19 years).

There are seven stable isotopes of mercury with the longest-lived radioisotopes being 194 Hg (half-life = 444 years) and 203 Hg (half-life = 47 days). 199 Hg and 201 Hg are the most often studied NMR-active nuclei, having spins of 1 / 2 and 3 / 2 respectively.


A summary of the physical properties of the Group 12 metals is given in [link] . Because of the n s electron in the Group 12 metals are tightly bound, and hence relatively unavailable for metallic bonding, the metals are volatile with low boiling points, as compared to the Group 2 metals.

Selected physical properties of the Group 12 metals.
Element Mp (°C) Bp (°C) Density (g/cm 3 )
Zn 419.53 907 7.14
Cd 321.07 767 8.65
Hg -38.83 356.73 13.534 (liquid)

The most notable anomaly in the Group 12 metals is the low melting point of mercury compared to zinc and cadmium. In order to completely understand the reasons for mercury’s low melting point quantum physics is required; however, the key point is that mercury has a unique electronic configuration, i.e., [Xe] 5 d 6 s . The stability of the 6 s shell is due to the presence of a filled 4 f shell, because an f shell poorly screens the nuclear charge that increases the attractive coulomb interaction of the 6 s shell and the nucleus. Such a configuration strongly resists removal of an electron and as such mercury behaves similarly to noble gas elements, which form weakly bonded and thus easily melting solids ( [link] ).

Liquid mercury.

Industrial production

The vast majority (95%) of zinc is mined from of the zinc sulfide ores. The zinc is most often mixed with copper, lead, and iron. Zinc metal is produced by extraction, in which the ore is ground and then the minerals are separated from the gangue (commercially worthless mineral matter) by froth flotation (a process for selectively separating hydrophobic materials from hydrophilic). Roasting converts the zinc sulfide concentrate produced to zinc oxide, [link] . Reduction of the zinc oxide with carbon, [link] , or carbon monoxide, [link] , at 950 °C into the metal is followed by distillation of the metal. Since cadmium is a common impurity in zinc ores, it is most often isolated during the production of zinc. Cadmium is isolated from the zinc metal by vacuum distillation if the zinc is smelted, or cadmium sulfate is precipitated out of the electrolysis solution.

Mercury is extracted by heating cinnabar (HgS) in a current of air, [link] , and condensing the vapor.

Questions & Answers

what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
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Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
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Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
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how did you get the value of 2000N.What calculations are needed to arrive at it
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Source:  OpenStax, Chemistry of the main group elements. OpenStax CNX. Aug 20, 2010 Download for free at http://cnx.org/content/col11124/1.25
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