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Barium hydroxide

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Title: Barium hydroxide  
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Barium hydroxide

Barium hydroxide
Identifiers
 Y
(monohydrate) N
(octahydrate) N
ChEBI  Y
ChemSpider  Y
Jmol-3D images Image
PubChem
RTECS number CQ9200000
Properties
Ba(OH)2
Molar mass 171.34 g/mol (anhydrous)
189.39 g/mol (monohydrate)
315.46 g/mol (octahydrate)
Appearance white solid
Density 3.743 g/cm3 (monohydrate)
2.18 g/cm3 (octahydrate, 16 °C)
Melting point 78 °C (172 °F; 351 K) (octahydrate)
300 °C (monohydrate)
407 °C (anhydrous)
Boiling point 780 °C (1,440 °F; 1,050 K)
mass of BaO (not Ba(OH)2):
1.67 g/100 mL (0 °C)
3.89 g/100 mL (20 °C)
4.68 g/100 mL (25 °C)
5.59 g/100 mL (30 °C)
8.22 g/100 mL (40 °C)
11.7 g/100 mL (50 °C)
20.94 g/100 mL (60 °C)
101.4 g/100 mL (100 °C)
Solubility in other solvents low
Basicity (pKb) -2.02
1.50 (octahydrate)
Structure
octahedral
Thermochemistry
−944.7 kJ/mol
Hazards
Safety data sheet See: data page
Harmful (Xn)
R-phrases R20/22
S-phrases (S2), S28
NFPA 704
0
3
0
Flash point Non-flammable
Related compounds
Other anions
Barium oxide
Barium peroxide
Other cations
Calcium hydroxide
Strontium hydroxide
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Thermodynamic
data
Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
 N  (: Y/N?)

Barium hydroxide are chemical compounds with the chemical formula Ba(OH)2(H2O)x. The monohydrate (x =1) is known as baryta, or baryta-water, it is one of the principal compounds of barium. This white granular monohydrate is the usual commercial form.

Contents

  • Preparation and structure 1
  • Uses 2
    • Laboratory uses 2.1
  • Reactions 3
  • Safety 4
  • See also 5
  • References 6
  • External links 7

Preparation and structure

Barium hydroxide can be prepared by dissolving barium oxide (BaO) in water:

BaO + 9 H2O → Ba(OH)2·8H2O

It crystallises as the octahydrate, which converts to the monohydrate upon heating in air. At 100 °C in a vacuum, the monohydrate gives BaO.[1] The monohydrate adopts a layered structure (see picture above). The Ba2+ centers adopt a square anti-prismatic geometry. Each Ba2+ center is bound by two water ligands and six hydroxide ligands, which are respectively doubly and triply bridging to neighboring Ba2+ centers. sites.[2] In the octahydrate, the individual Ba2+ centers are again eight coordinate but do not share ligands.[3]

Coordination sphere about an individual barium ion in Ba(OH)2.H2O.

Uses

Industrially, barium hydroxide is used as the precursor to other barium compounds. The monohydrate is used to dehyrate and remove sulfate from various products.[4] This application exploits the very low solubility of barium sulfate. This industrial application is also applied to laboratory uses.

Laboratory uses

Barium hydroxide is used in sodium hydroxide and potassium hydroxide, as barium carbonate is insoluble in water. This allows the use of indicators such as phenolphthalein or thymolphthalein (with alkaline colour changes) without the risk of titration errors due to the presence of carbonate ions, which are much less basic.[5]

Barium hydroxide is occasionally used in

  • Material Safety Data Sheet (MSDS)

External links

  1. ^ (1960). Gmelins Handbuch der anorganischen Chemie (8. Aufl.), Weinheim: Verlag Chemie, p. 289.
  2. ^ Kuske, P.; Engelen, B.; Henning, J.; Lutz, H.D.; Fuess, H.; Gregson, D. "Neutron diffraction study of Sr(OH)2(H2O) and beta-Ba(OH)2*(H2O)" Zeitschrift fuer Kristallographie (1979-2010) 1988, vol. 183, p319-p325.
  3. ^ Manohar, H.; Ramaseshan, S. "The crystal structure of barium hydroxide octahydrate Ba (OH)2(H2O)8" Zeitschrift fuer Kristallographie, Kristallgeometrie, Kristallphysik, Kristallchemie 1964. vol. 119, p357-p374
  4. ^ Robert Kresse, Ulrich Baudis, Paul Jäger, H. Hermann Riechers, Heinz Wagner, Jochen Winkler, Hans Uwe Wolf, "Barium and Barium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2007 Wiley-VCH, Weinheim. doi:10.1002/14356007.a03_325.pub2
  5. ^ Mendham, J.; Denney, R. C.; Barnes, J. D.; Thomas, M. J. K. (2000), Vogel's Quantitative Chemical Analysis (6th ed.), New York: Prentice Hall,  
  6. ^ Meyer, K.; Bloch, H. S. (1945). "Naphthoresorcinol". Org. Synth. 25: 73; Coll. Vol. 3: 637.
  7. ^ Brown, G. B. (1946). "Methylsuccinic acid". Org. Synth. 26: 54; Coll. Vol. 3: 615.
  8. ^ Ford, Jared H. (1947). "β-Alanine". Org. Synth. 27: 1; Coll. Vol. 3: 34.
  9. ^ Anslow, W. K.; King, H.; Orten, J. M.; Hill, R. M. (1925). "Glycine". Org. Synth. 4: 31; Coll. Vol. 1: 298.
  10. ^ Durham, L. J.; McLeod, D. J.; Cason, J. (1958). "Methyl hydrogen hendecanedioate". Org. Synth. 38:55; Coll. Vol. 4:635.
  11. ^ [2]
  12. ^ Thorpe, J. F.; Kon, G. A. R. (1925). "Cyclopentanone". Org. Synth. 5: 37; Coll. Vol. 1: 192.
  13. ^ Conant, J. B.; Tuttle, Niel. (1921). "Diacetone alcohol". Org. Synth. 1: 45; Coll. Vol. 1: 199.
  14. ^ Karabinos, J. V. (1956). "-Gulonic γ-lactoneD". Org. Synth. 36: 38; Coll. Vol. 4: 506.
  15. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  16. ^ "Endothermic Reactions of Hydrated Barium Hydroxide and Ammonium Chloride". UC San Diego. Retrieved 2 April 2014. 
  17. ^ Endothermic Solid-Solid Reactions
  18. ^ a b Camp, Eric. "Endothermic Reaction". Univertist of Washington. Retrieved 2 April 2014. 
  19. ^ "Endothermic solid-solid reactions" (PDF). Classic Chemistry Demonstrations. The Royal Society of Chemistry. Retrieved 2 April 2014. 

References

See also

Barium hydroxide presents the same hazards as other strong bases and as other water-soluble barium compounds: it is corrosive and toxic.

Safety

Reactions of barium hydroxide with ammonium salts are strongly endothermic. The reaction of barium hydroxide octahydrate with ammonium chloride[16] [17] or[18] ammonium thiocyanate[18][19] is often used as a classroom chemistry demonstration, producing temperatures cold enough to freeze water and enough water to dissolve the resulting mixture.

Barium hydroxide decomposes to barium oxide when heated to 800 °C. Reaction with carbon dioxide gives barium carbonate. Its aqueous solution, being highly alkaline, undergoes neutralization reactions with acids. Thus, it forms barium sulfate and barium phosphate with sulfuric and phosphoric acids, respectively. Reaction with hydrogen sulfide produces barium sulfide. Precipitation of many insoluble, or less soluble barium salts, may result from double replacement reaction when a barium hydroxide aqueous solution is mixed with many solutions of other metal salts. [15]

Reactions

It is also used in the preparation of cyclopentanone,[12] diacetone alcohol[13] and D-Gulonic γ-lactone.[14]

Barium hydroxide is used, as well, in the decarboxylation of amino acids liberating barium carbonate in the process. [11]

It has been used to hydrolyse one of the two equivalent ester groups in dimethyl hendecanedioate.[10]

[9][8][7] and nitriles.[6]

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