Periodic Table > Barium
 

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 727 oC, 1340.6 oF, 1000.15 K 
Period Boiling point 1845 oC, 3353 oF, 2118.15 K 
Block Density (kg m-3) 3594 
Atomic number 56  Relative atomic mass 137.327  
State at room temperature Solid  Key isotopes 138Ba 
Electron configuration [Xe] 6s2  CAS number 7440-39-3 
ChemSpider ID 4511436 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
Digestive disorder. The image used here is based on X-ray photographs of the human stomach and intestines in patients who have been given a “Barium meal”.
Appearance
A soft silvery metal that rapidly tarnishes in air and reacts with water. ‘Barium meal’ and ‘barium enemas’ (barium sulfate) are given to patients suffering from digestive disorders : the action of the stomach and intestines can be seen as the metal’s progress through the body is revealed by X-rays. Most barium sulfate is now used in drilling fluids for oil and gas wells, and several million tonnes a year are manufactured.
Uses
Barium is not an extensively used element. The best-known use is in the form of barium sulfate, which can be drunk as a medical cocktail to outline the stomach and intestines for medical examination. The sulfate is also used in paint and in glassmaking. Barium carbonate has been used as a rat poison. Barium nitrate gives fireworks a green colour.
Biological role
Barium and all its compounds that are water or acid soluble are toxic.
Natural abundance
Barium occurs only in combination with other elements, chiefly in the ores barytes and witherite. It can be prepared by electrolysis of the chloride, or by heating barium oxide with aluminium.
 
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) 2.680 Covalent radius (Å) 2.06
Electron affinity (kJ mol-1) 13.949 Electronegativity
(Pauling scale)
0.890
Ionisation energies
(kJ mol-1)
 
1st
502.852
2nd
965.222
3rd
-
4th
-
5th
-
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 5.0
Country with largest reserve base China
Crustal abundance (ppm) 456
Leading producer China
Reserve base distribution (%) 40.90
Production concentration (%) 40.50
Total governance factor(production) 9
Top 3 countries (mined)
  • 1) China
  • 2) Kazakhstan
  • 3) India
Top 3 countries (production)
  • 1) China
  • 2) India
  • 3) Morocco
 

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 2
Isotopes Isotope Atomic mass Natural abundance (%) Half life Mode of decay
  130Ba 129.906 0.106 2.2 x 1021 β+β+ 
  132Ba 131.905 0.101 1.3 x 1021 EC EC 
  134Ba 133.905 2.417
  135Ba 134.906 6.592
  136Ba 135.905 7.854
  137Ba 136.906 11.232
  138Ba 137.905 71.698
 

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)
28.07 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)
- 7.97
x 10-6
4.5
x 10-2
7.11 162 - - - - - -
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History

In the early 1600s, Vincenzo Casciarolo, of Bologna, Italy, found some unusual pebbles. If they were heated to redness during the day, they would shine during the night. This was the mineral barite (barium sulfate, BaSO4).


When Bologna stone, as it became known, was investigated by Carl Scheele in 1760s he realised it was the sulfate of an unknown element. Meanwhile a mineralogist, Dr William Withering, had found another curiously heavy mineral in a lead mine in Cumberland which clearly was not a lead ore. He named it witherite; it was later shown to be barium carbonate, BaCO3.


Neither the sulfate nor the carbonate yielded up the metal itself using the conventional process of smelting with carbon. However, Humphry Davy at the Royal Institution in London produced it by the electrolysis of barium hydroxide in 1808.

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Podcasts

Listen to Barium Podcast
Transcript :

Chemistry in Its Element - Barium


  (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, this week rat poison, fireworks, fine glass, oil exploration and enemas.   Spotted the link yet, well the answer is sitting in the apple green element at the bottom of group two.

 

Adina Payton

 

For many, barium has an unpleasant association. The first thing most people think about when this element is mentioned is the "barium enema" or "barium swallow". Sickly memories often surface of the radiology clinic - where they even ask which flavor you would like strawberry or banana...   These "cocktails" consist of a white fluid of barium sulfate that is either "squirted" up one orifice or swallowed down another.   It is used to help diagnose diseases and other problems that affect the large intestine or the esophagus. The heavy barium blocks X-rays, causing the filled part of the digestive system to show up clearly on the X-ray picture or CT scan. Barium sulfate can be taken into our body because it is highly insoluble in water, and is eliminated completely from the digestive tract. And if this sounds like an unpleasant experience, it's lucky that it's barium sulfate and not just barium that is used for the exam. 

Barium is a highly toxic metal. It's extremely poisonous - no one in their right mind would consider consuming it.   At low doses, it acts as a muscle stimulant, while higher doses play havoc with the nervous system, causing an irregular heartbeat, tremor, weakness, anxiety, paralysis, and potentially death as the heart and lungs fail. Acute doses of less than 1 gram can be fatal to humans.   Indeed barium carbonate is useful as rat poison. Unlike barium sulfate, barium carbonate dissolves in stomach acid, releasing the poisonous barium to do its rather nasty but efficient work.

Conveniently Barium, which is a soft silvery metallic alkaline earth metal, is never found in nature in its pure form, due to its reactivity with air or in water. In fact the metal is a "getter" in vacuum tubes, meaning it's used to remove the last traces of oxygen.

Barium compounds are notable for their high specific gravity - which, in practical terms, means the compounds are extremely heavy. This is true of the most common barium-bearing mineral, its sulfate - barite BaSO4 -   is called 'heavy spar' due to the high density (4.5 g/cm³   - the size of a pea). Indeed the name barium comes from the Greek barys, meaning "heavy". Due to its density barium compounds, and especially barite (BaSO4), are extremely important to the petroleum industry. Barite is used in drilling mud, a weighting agent in drilling new oil wells.

Barium carbonate also has an application that is more appealing than rat poison - it's used in glassmaking to enhance the luster of the glass. And barite is used in paints, bricks, tiles, glass and rubber production; barium nitrate and chlorate give green colors to fireworks and barium titanate was proposed in 2007 to be used in next generation battery technology for electric cars.   Despite the relative high abundance of barium sulfate in nature - it's the 14th most abundant element in earths crust - due to its multiple uses it has a high value, in the range of $55/100grams.   Total annual world production is estimated at around 6,000,000 tons. And the main mining areas are the UK, Italy, the Czech Republic, USA and Germany. Total world reserves are estimated to be around 450,000,000 tons.

And why am I so particularly interested in this heavy, poisonous element? Well, as a scientist I actually study barite - I separate barite from marine sediments - the mud at the bottom of the sea - and analyze its chemistry which tells us fabulous stories about seawater chemistry and productivity in the geological past.   Barite forms in proportion to ocean productivity - the activity of marine phytoplankton the floating "trees" of the ocean which are the base of the marine food chain - and accumulates in marine sediments. The accumulation of barite in ocean sediments can tell us how productive the ocean was at any given time in Earth's history. Barite in contrast to many other minerals is not soluble and is preserved over many millions of years recording the chemistry of the ocean and how it changed over time.  

And therefore it's a great archive of ocean history.

Chris Smith

Chemist Adina Payton telling the tale of Barium.   And talking of what sits at the bottom of the oceans.

Steve Mylon

 

"How did it smell?" That was the only question I needed to ask a geologist colleague of mine about the sediment she was trying to understand.   The smell of the sediment tells a great deal about the underlying chemistry.   Thick black anoxic sediments can be accompanied by a putrid smell which is unique to reduced sulfur.  

Maybe this is why sulfur has such a bad reputation. My son wouldn't eat eggs for 6 months when he got a smell of his first rotten one.  

 

 

Chris Smith

That's the stinky story of Sulfur with Steve Mylon on next week's Chemistry in its Element, I hope you can join us.   I'm Chris Smith, thank you for listening and goodbye. 

(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 :
In this experiment you will be observing and interpreting the changes when drops of solutions of various anions are added to drops of solutions of Group 2 element cations.
Description :
Some reactions of carbon dioxide
Description :
In this experiment the pH of various oxides is tested.
Description :
Assessment for Learning is an effective way of actively involving students in their learning.  Each session plan comes with suggestions about how to organise activities and worksheets that may be use...
Description :
Metals in Group 2 of the Periodic Table are less reactive than those in Group 1. This experiment indicates the relative reactivity of elements within the group.
Description :
In this experiment you will be looking to see whether precipitates form when you add drops of solutions of sulphates or carbonates to drops of solutions of Group 1 or 2 metal ions.
 

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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.