Periodic Table > Zirconium
 

Terminology


Allotropes
Some elements exist in several different structural forms, these are called allotropes.


For more information on Murray Robertson’s image see Uses/Interesting Facts below.

 

Fact Box Terminology


Group
Elements appear in columns or ‘groups’ in the periodic table. Members of a group typically have similar properties and electron configurations in their outer shell.


Period
Elements are laid out into rows or ‘periods’ so that similar chemical behaviour is observed in columns.


Block
Elements are organised into blocks by the orbital type in which the outer electrons are found. These blocks are named for the characteristic spectra they produce: sharp, principal, diffuse, and fundamental.


Atomic Number
The number of protons in the nucleus.


Atomic Radius/non -bonded (Å)
based on Van der Waals forces (where several isotopes exist, a value is presented for the most prevalent isotope). These values were calculated using a multitude of methods including crystallographic data, gas kinetic collision cross sections, critical densities, liquid state properties, for more details please refer to the CRC Handbook of Chemistry and Physics.


Electron Configuration
The arrangements of electrons above the last (closed shell) noble gas.


Isotopes
Elements are defined by the number of protons in its centre (nucleus), whilst the number of neutrons present can vary. The variations in the number of neutrons will create elements of different mass which are known as isotopes.


Melting Point (oC)
The temperature at which the solid-liquid phase change occurs.


Melting Point (K)
The temperature at which the solid-liquid phase change occurs.


Melting Point (oF)
The temperature at which the solid-liquid phase change occurs.


Boiling Point (oC)
The temperature at which the liquid-gas phase change occurs.


Boiling Point (K)
The temperature at which the liquid-gas phase change occurs.


Boiling Point (oF)
The temperature at which the liquid-gas phase change occurs.


Sublimation
Elements that do not possess a liquid phase at atmospheric pressure (1 atm) are described as going through a sublimation process.


Density (kgm-3)
Density is the weight of a substance that would fill 1 m3 (at 298 K unless otherwise stated).


Relative Atomic Mass
The mass of an atom relative to that of Carbon-12. This is approximately the sum of the number of protons and neutrons in the nucleus. Where more than one isotope exists the value given is the abundance weighted average.


Key Isotopes (% abundance)
An element must by definition have a fixed number of protons in its nucleus, and as such has a fixed atomic number, however variants of an element can exist with differing numbers of neutrons, and hence a different atomic masses (e.g. 12C has 6 protons and 6 neutrons and 13C has 6 protons and 7 neutrons).


CAS number
The Chemical Abstracts Service registry number is a unique identifier of a particular chemical, designed to prevent confusion arising from different languages and naming systems (where several isotopes exist, a value is presented for the most prevalent isotope).

Fact Box

 
Group Melting point 1854 oC, 3369.2 oF, 2127.15 K 
Period Boiling point 4406 oC, 7962.8 oF, 4679.15 K 
Block Density (kg m-3) 6507 
Atomic number 40  Relative atomic mass 91.224  
State at room temperature Solid  Key isotopes 90Zr, 92Zr, 94Zr 
Electron configuration [Kr] 4d25s2  CAS number 7440-67-7 
ChemSpider ID 22431 ChemSpider is a free chemical structure database
 

Interesting Facts terminology


Image Explanation

Murray Robertson is the artist behind the images which make up Visual Elements. This is where the artist explains his interpretation of the element and the science behind the picture.


Natural Abundance

Where this element is most commonly found in nature.


Biological Roles

The elements role within the body of humans, animals and plants. Also functionality in medical advancements both today and years ago.


Appearance

The description of the element in its natural form.

Uses / Interesting Facts

 
Image explanation
Ancient Egyptians used zircon in jewellery. The scarab beetle served as a symbol of regeneration and creation conveying ideas of transformation, renewal, and resurrection.
Appearance
A hard, silvery metal that is very resistant to corrosion and used in nuclear reactors since it does not absorb neutrons. The oxide is used to make heat-resistant crucibles, foundry bricks, ceramics and abrasives, and it is so strong that even scissors and knives can be made from it. Large crystals of zircon are cut as gem stones and have a golden hue, which is how the element was first discovered and given its name.
Source

Uses
Zirconium has very low absorption for neutrons, and is therefore useful in nuclear energy applications. More than 90% of zirconium production is used in this field, as reactors use many metres of zirconium alloy tubing. Zirconium is exceptionally resistant to corrosion by most agents including sea water, acids and alkalis, and so is used extensively by the chemical industry where corrosive agents are in use. With niobium, zirconium is superconductive at low temperatures and is used to make superconductive magnets. Impure zirconium(IV) oxide is used for crucibles which will withstand heat shock, for furnace linings, and by the glass and ceramics industries. It is also used in the making of microwave filters.
Biological role
Zirconium has no known biological role. It is non-toxic.
Natural abundance
Zirconium occurs in about 30 mineral species, the major ones being baddeleyite and zircon, found in Brazil. It is produced commercially by reduction of the chloride with magnesium.
 
Atomic Data Terminology

Atomic radius/non -bonded (Å)
Based on Van der Waals forces (where several isotopes exist, a value is presented for the most prevalent isotope). These values were calculated using a multitude of methods including crystallographic data, gas kinetic collision cross sections, critical densities, liquid state properties,for more details please refer to the CRC Handbook of Chemistry and Physics.


Electron affinity (kJ mol-1)
The energy released when an additional electron is attached to the neutral atom and a negative ion is formed (where several isotopes exist, a value is presented for the most prevalent isotope). *


Electronegativity (Pauling scale)
The degree to which an atom attracts electrons towards itself, expressed on a relative scale as a function bond dissociation energies, Ed in eV. χA - χB =(eV)-1/2sqrt(Ed(AB)-[Ed(AA)+Ed(BB)]/2), with χH set as 2.2 (where several isotopes exist, a value is presented for the most prevalent isotope).


1st Ionisation energy (kJ mol-1)
The minimum energy required to remove an electron from a neutral atom in its ground state (where several isotopes exist, a value is presented for the most prevalent isotope).


Covalent radius (Å)
The size of the atom within a covalent bond, given for typical oxidation number and coordination (where several isotopes exist, a value is presented for the most prevalent isotope). ***

Atomic Data

 
Atomic radius, non-bonded (Å) 2.230 Covalent radius (Å) 1.64
Electron affinity (kJ mol-1) 41.088 Electronegativity
(Pauling scale)
1.330
Ionisation energies
(kJ mol-1)
 
1st
640.074
2nd
1263.957
3rd
2218.196
4th
3313.304
5th
7752.397
6th
-
7th
-
8th
-
 

Mining/Sourcing Information

Data for this section of the data page has been provided by the British Geological Survey. To review the full report please click here or please look at their website here.


Key for numbers generated


Governance indicators

1 (low) = 0 to 2

2 (medium-low) = 3 to 4

3 (medium) = 5 to 6

4 (medium-high) = 7 to 8

5 (high) = 9


Reserve base distribution

1 (low) = 0 to 30 %

2 (medium-low) = 30 to 45 %

3 (medium) = 45 to 60 %

4 (medium-high) = 60 to 75 %

5 (high) = 75 %

(Where data are unavailable an arbitrary score of 2 was allocated. For example, Be, As, Na, S, In, Cl, Ca and Ge are allocated a score of 2 since reserve base information is unavailable. Reserve base data are also unavailable for coal; however, reserve data for 2008 are available from the Energy Information Administration (EIA).)


Production Concentration

1 (low) = 0 to 30 %

2 (medium-low) = 30 to 45 %

3 (medium) = 45 to 60 %

4 (medium-high) = 60 to 75 %

5 (high) = 75 %


Crustal Abundance

1 (low) = 100 to 1000 ppm

2 (medium-low) =10 to 100 ppm

3 (medium) = 1 to 10 ppm

4 (medium-high) = 0.1 to 1 ppm

5 (high) = 0.1 ppm

(Where data are unavailable an arbitrary score of 2 was allocated. For example, He is allocated a score of 2 since crustal abundance data is unavailable.)


Explanations for terminology


Crustal Abundance (ppm)

The abundance of an element in the Earth's crust in parts-per-million (ppm) i.e. The number of atoms of this element per 1 million atoms of crust.


Sourced

The country with the largest reserve base.


Reserve Base Distribution

This is a measure of the spread of future supplies, recording the percentage of a known resource likely to be available in the intermediate future (reserve base) located in the top three countries.


Production Concentrations

This reports the percentage of an element produced in the top three countries. The higher the value, the larger risk there is to supply.


Total Governance Factor

The World Bank produces a global percentile rank of political stability. The scoring system is given below, and the values for all three production countries were summed.


Relative Supply Risk Index

The Crustal Abundance, Reserve Base Distribution, Production Concentration and Governance Factor scores are summed and then divided by 2, to provide an overall Relative Supply Risk Index.

Supply Risk

 
Scarcity factor 4.5
Country with largest reserve base Australia
Crustal abundance (ppm) 132
Leading producer Australia
Reserve base distribution (%) 45.50
Production concentration (%) 33.50
Total governance factor(production) 6
Top 3 countries (mined)
  • 1) Australia
  • 2) South Africa
  • 3) Ukraine
Top 3 countries (production)
  • 1) Australia
  • 2) South Africa
  • 3) China
 

Oxidation states/ Isotopes


Key for Isotopes


Half Life
  y years
  d days
  h hours
  m minutes
  s seconds
Mode of decay
  α alpha particle emission
  β negative beta (electron) emission
  β+ positron emission
  EC orbital electron capture
  sf spontaneous fission
  ββ double beta emission
  ECEC double orbital electron capture

Terminology


Common Oxidation states
The oxidation state of an atom is a measure of the degree of oxidation of an atom. It is defined as being the charge that an atom would have if all bonds were ionic. Free atoms have an oxidation state of 0, and the sum of oxidation numbers within a substance must equal the overall charge.


Important Oxidation states
The most common oxidation states of an element in its compounds.


Isotopes
Elements are defined by the number of protons in its centre (nucleus), whilst the number of neutrons present can vary. The variations in the number of neutrons will create elements of different mass which are known as isotopes.

Oxidation States / Isotopes

 
Common oxidation states 4
Isotopes Isotope Atomic mass Natural abundance (%) Half life Mode of decay
  90Zr 89.905 51.45
  91Zr 90.906 11.22
  92Zr 91.905 17.15
  94Zr 93.906 17.38 > 1017 β-β- 
  96Zr 95.908 2.8 2.3 x 1019 β-β- 
        > 1.7 x18 β- 
 

Pressure and Temperature - Advanced Terminology


Molar Heat Capacity (J mol-1 K-1)

Molar heat capacity is the energy required to heat a mole of a substance by 1 K.


Young's modulus (GPa)

Young's modulus is a measure of the stiffness of a substance, that is, it provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain.


Shear modulus (GPa)

The shear modulus of a material is a measure of how difficult it is to deform a material, and is given by the ratio of the shear stress to the shear strain.


Bulk modulus (GPa)

The bulk modulus is a measure of how difficult to compress a substance. Given by the ratio of the pressure on a body to the fractional decrease in volume.


Vapour Pressure (Pa)

Vapour pressure is the measure of the propensity of a substance to evaporate. It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system.

Pressure / Temperature - Advanced

 
Molar heat capacity
(J mol-1 K-1)
25.36 Young's modulus (GPa) Unknown
Shear modulus (GPa) Unknown Bulk modulus (GPa) Unknown
Vapour pressure  
Temperature (K)
400 600 800 1000 1200 1400 1600 1800 2000 2200 2400
Pressure (Pa)
- - - - - 1.05
x 10-10
6.17
x 10-8
8.68
x 10-6
4.5
x 10-4
1.1
x 10-2
0.16
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History

Gems that contain zirconium were known in ancient times as zircon. In 1789, the German chemist, Martin Klaproth analysed a zircon and separated zirconium in the form of its ‘earth’ zirconia, which is the oxide ZrO2.


Klaproth failed to isolate the pure metal itself, and Humphry Davy also failed when he tried electrolysis in 1808. It was not until 1824 that the element was isolated, when the Swedish chemist Jöns Berzelius heated potassium hexafluorozirconate (K2ZrF6) with potassium metal and obtained some zirconium as a black powder.


Totally pure zirconium was only produced in 1925 by the Dutch chemists Anton Eduard van Arkel and Jan Hendrik de Boer by the decomposition of zirconium tetraiodide (ZrI4). These days the metal is produced in bulk by heating zirconium tetrachloride (ZrCl4) with magnesium.

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Podcasts

Listen to Zirconium Podcast
Transcript :

Chemistry in Its Element - Zirconium


  (Promo)

 

You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry

(End promo)

 

Chris Smith

Hello and welcome to our tour of the unusual, exciting and deadly aspects of the elements that make up the world around us.   We're kicking off our journey through the Periodic Table with a chemical that sometimes masquerades as diamond but is equally at home in the core of a nuclear reactor or even in an ironworks.   To tell the story of this mysterious entity which is otherwise known as Zirconium, here's chemist and award winning author John Emsley.  

 

John Emsley

Zirconium.   Wear it flashing on your finger, or unseen within your frame, it holds the key to nuclear energy, and it's got a gem-like name. It's zirconium.

 

The name zirconium comes from the Arabic word zargun which refers to a golden-hued gemstone known since Biblical times called zircon. Today artificial gems are made from Zirconium oxide known as cubic zirconia and they sparkle with more brilliance than diamond although they are not as hard. What distinguishes them from real diamond is their higher density of 6.0 g cm-3 compared to diamond's 3.52.

Zirconium is abundant in S-type stars in which heavier elements are formed by neutron capture. Traces are also present in the Sun. Rock brought back from the moon was found to have a surprisingly high zirconium content. Down here on Earth zircons has shown that life might have started much earlier than once thought. These were found in Australia in the year 2000 were 4.4 billion years old, and their oxygen isotope ratio of O16/O18 showed they could only have been formed when there was liquid water on the surface of the Earth, and this was nearly 500 million years earlier than previously assumed.

In the Middle Ages colourless gemstones of zircon were thought to be an inferior kind of diamond, but that was shown to be wrong when a German chemist, Martin Klaproth (1743-1817), analysed one in 1789 and discovered zirconium. Klaproth was unable to isolate the metal itself. That was achieved in 1824 by the Swedish chemist Jöns Jacob Berzelius but there was little use for it or its chemical compounds, and so it languished for a century or more.

Today this element is widely used, as zircon, as Zirconium oxide and as the metal itself. Zirconium is to be found in ceramics, foundry equipment, glass, chemicals, and metal alloys.

Zircon sand is used for heat-resistant linings for furnaces, for giant ladles for molten metal, and to make foundry moulds. Mixed with vanadium or praseodymium zircon makes blue and yellow pigments for glazing pottery and tiles.

Zirconium oxide is used to make heat resistant crucibles, ceramics and abrasives. A red-hot crucible made from it can be plunged into cold water without cracking. Zirconium oxide is to be found in ultra-strong ceramics that are stronger and sharper even than toughened steel and are used for knives, scissors and golf irons. Production of pure zirconium oxide is almost 25 000 tons per year, and it also goes into various chemicals that end up as cosmetics, antiperspirants, food packaging, and even fake gems. The paper and packaging industry is finding zirconium compounds make good surface coatings because they have excellent water resistance and strength. Equally important is their low toxicity. 

Zirconium metal has an oxidised surface which is both hard and impervious to chemical attack making it ideal not only for chemical plants but for body implants such as hip replacement joints. Zirconium-aluminium alloy is used for top of the range bicycle frames because it combines strength and lightness.

Zirconium metal had some hidden assets which suddenly brought it to prominence in the late 1940s; it was found to be the ideal metal for inside nuclear reactors and nuclear submarines. It does not corrode at high temperatures, nor absorb neutrons to form radioactive isotopes. Even today the nuclear industry buys almost all of the metal that is produced and some nuclear reactors have more than 100 kilometres of zirconium tubing. Zirconium is used to make the cladding for uranium oxide fuel elements. As mined, zirconium contains 1-3% per cent of hafnium, which is chemically very similar, and although it is difficult to separate the two elements this has to be done for the metal used in the nuclear industry because hafnium absorbs neutrons very strongly.

Finally, we have two zirconium materials with extreme properties, one which it displays when very cold, the other when it is heated to high temperatures. The first is a zirconium-niobium alloy which becomes superconducting below 35 Kelvin (- 238oC) in other words it will conduct electricity with no loss of energy. The second is zirconium tungstate (ZrW2O8) which actually shrinks as you heat it up, at least until it reaches 700oC when it decomposes into the two metal oxides.

 

 

 

Chris Smith

John Emsley unlocking the secrets of element number 40, Zirconium.   And you can find out some more about John's favourite elements in a series he has written for the RSC's Education in Chemistry which is online at rsc.org/education.   Next time on Chemistry in its Element, life's a gas with Mark Peplow.

 

Mark Peplow

Little did those humble Cyanobacteria realize what they were doing when two and a half billion years ago, they started to build up their own reserves of energy-rich chemicals, by combining water and carbon dioxide. Powered by sunlight, they spent the next two billion years terraforming our entire planet with the waste product of their photosynthesis, a rather toxic gas called Oxygen. 

 

Chris Smith

So join us next week for a breath of fresh air and the story of Oxygen.   I'm Chris Smith, thanks for listening, see you next time. 

 

(Promo)

 

Chemistry in its elementis brought to you by the Royal Society of Chemistry and produced by thenakedscientists dot com. There's more information and other episodes of Chemistry in its element on our website at chemistryworld dot org forward slash elements. 

 

(End promo)

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Resources

Description :
Assessment for Learning is an effective way of actively involving students in their learning. This is a series of plans based around chemistry topics.
Description :
When concentrated hydrochloric acid is added to a very dilute solution of copper sulfate, the pale blue solution slowly turns yellow-green on the formation of a copper chloride complex. When concentr...
Description :
The purpose of this experiment is to observe and interpret some of the chemistry of three first row transition elements and to compare them with a typical s-block element.
Description :
The Periodic Table allows chemists to see similarities and trends in the properties of chemical elements. This experiment illustrates some properties of the common transition elements and their compo...
Description :
In this experiment you will be looking at a group of transition elements chromium, molybdenum and tungsten.
Description :
The purpose of this experiment is to examine some of the solution chemistry of the transition elements.
 

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References

 
Images:  Visual Elements © Murray Robertson 2011
Mining and Sourcing data:  British Geological Survey – natural environment research council.
Text:  John Emsley Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, 2nd Edition, 2011.
Additional information for platinum, gold, neodymium and dysprosium obtained from Material Value Consultancy Ltd www.matvalue.com
Data: CRC Handbook of Chemistry and Physics, CRC Press, 92nd Edition, 2011.
G. W. C. Kaye and T. H. Laby Tables of Physical and Chemical Constants, Longman, 16th Edition, 1995.
Members of the RSC can access these books through our library.