Tin(II) oxide
IUPAC name
Tin(II) oxide
Other names
Stannous oxide
Tin monoxide
3D model (JSmol)
ECHA InfoCard 100.040.439 Edit this at Wikidata
EC Number
  • 244-499-5
RTECS number
  • XQ3700000
  • InChI=1S/O.Sn
  • O=[Sn]
Molar mass 134.709 g/mol
Appearance black or red powder when anhydrous, white when hydrated
Density 6.45 g/cm3
Melting point 1,080 °C (1,980 °F; 1,350 K)[1]
−19.0·10−6 cm3/mol
56 J·mol−1·K−1[2]
−285 kJ·mol−1[2]
Flash point Non-flammable
NIOSH (US health exposure limits):
PEL (Permissible)
REL (Recommended)
TWA 2 mg/m3[3]
IDLH (Immediate danger)
Safety data sheet (SDS) ICSC 0956
Related compounds
Other anions
Tin sulfide
Tin selenide
Tin telluride
Other cations
Carbon monoxide
Silicon monoxide
Germanium(II) oxide
Lead(II) oxide
Related tin oxides
Tin dioxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Tin(II) oxide (stannous oxide) is a compound with the formula SnO. It is composed of tin and oxygen where tin has the oxidation state of +2. There are two forms, a stable blue-black form and a metastable red form.

Preparation and reactions

Tin(II) oxide burning

Blue-black SnO can be produced by heating the tin(II) oxide hydrate, SnO·xH2O (x<1) precipitated when a tin(II) salt is reacted with an alkali hydroxide such as NaOH.[4]
Metastable, red SnO can be prepared by gentle heating of the precipitate produced by the action of aqueous ammonia on a tin(II) salt.[4]
SnO may be prepared as a pure substance in the laboratory, by controlled heating of tin(II) oxalate (stannous oxalate) in the absence of air or under a CO2 atmosphere. This method is also applied to the production of ferrous oxide and manganous oxide.[5][6]

SnC2O4·2H2O → SnO + CO2 + CO + 2 H2O

Tin(II) oxide burns in air with a dim green flame to form SnO2.[4]

2 SnO + O2 → 2 SnO2

When heated in an inert atmosphere initially disproportionation occurs giving Sn metal and Sn3O4 which further reacts to give SnO2 and Sn metal.[4]

4SnO → Sn3O4 + Sn
Sn3O4 → 2SnO2 + Sn

SnO is amphoteric, dissolving in strong acid to give tin(II) salts and in strong base to give stannites containing Sn(OH)3.[4] It can be dissolved in strong acid solutions to give the ionic complexes Sn(OH2)32+ and Sn(OH)(OH2)2+, and in less acid solutions to give Sn3(OH)42+.[4] Note that anhydrous stannites, e.g. K2Sn2O3, K2SnO2 are also known.[7][8][9] SnO is a reducing agent and is thought to reduce copper(I) to metallic clusters in the manufacture of so-called "copper ruby glass".[10]


Black, α-SnO adopts the tetragonal PbO layer structure containing four coordinate square pyramidal tin atoms.[11] This form is found in nature as the rare mineral romarchite.[12] The asymmetry is usually simply ascribed to a sterically active lone pair; however, electron density calculations show that the asymmetry is caused by an antibonding interaction of the Sn(5s) and the O(2p) orbitals.[13] The electronic structure and chemistry of the lone pair determines most of the properties of the material.[14]

Non-stoichiometry has been observed in SnO.[15]

The electronic band gap has been measured between 2.5eV and 3eV.[16]


The dominant use of stannous oxide is as a precursor in manufacturing of other, typically divalent, tin compounds or salts. Stannous oxide may also be employed as a reducing agent and in the creation of ruby glass.[17] It has a minor use as an esterification catalyst.

Cerium(III) oxide in ceramic form, together with Tin(II) oxide (SnO) is used for illumination with UV light.[18]


  1. ^ Tin and Inorganic Tin Compounds: Concise International Chemical Assessment Document 65, (2005), World Health Organization
  2. ^ a b Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23. ISBN 978-0-618-94690-7.
  3. ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0615". National Institute for Occupational Safety and Health (NIOSH).
  4. ^ a b c d e f Egon Wiberg, Arnold Frederick Holleman (2001) Inorganic Chemistry, Elsevier ISBN 0-12-352651-5
  5. ^ Satya Prakash (2000),Advanced Inorganic Chemistry: V. 1, S. Chand, ISBN 81-219-0263-0
  6. ^ Arthur Sutcliffe (1930) Practical Chemistry for Advanced Students (1949 Ed.), John Murray - London.
  7. ^ Braun, Rolf Michael; Hoppe, Rudolf (1978). "The First Oxostannate(II): K2Sn2O3". Angewandte Chemie International Edition in English. 17 (6): 449–450. doi:10.1002/anie.197804491.
  8. ^ Braun, R. M.; Hoppe, R. (1982). "Über Oxostannate(II). III. K2Sn2O3, Rb2Sn2O3 und Cs2Sn2O3 - ein Vergleich". Zeitschrift für Anorganische und Allgemeine Chemie. 485: 15–22. doi:10.1002/zaac.19824850103.
  9. ^ R M Braun R Hoppe Z. Naturforsch. (1982), 37B, 688-694
  10. ^ Bring, T.; Jonson, B.; Kloo, L.; Rosdahl, J; Wallenberg, R. (2007), "Colour development in copper ruby alkali silicate glasses. Part I: The impact of tin oxide, time and temperature", Glass Technology, Eur. J. Glass Science & Technology, Part A, 48 (2): 101–108, ISSN 1753-3546
  11. ^ Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6
  12. ^ Ramik, R. A.; Organ, R. M.; Mandarino, J. A. (2003). "On Type Romarchite and Hydroromarchite from Boundary Falls, Ontario, and Notes on Other Occurrences". The Canadian Mineralogist. 41 (3): 649–657. doi:10.2113/gscanmin.41.3.649.
  13. ^ Walsh, Aron; Watson, Graeme W. (2004). "Electronic structures of rocksalt, litharge, and herzenbergite SnO by density functional theory". Physical Review B. 70 (23): 235114. Bibcode:2004PhRvB..70w5114W. doi:10.1103/PhysRevB.70.235114.
  14. ^ Mei, Antonio B.; Miao, Ludi; Wahila, Matthew J.; Khalsa, Guru; Wang, Zhe; Barone, Matthew; Schreiber, Nathaniel J.; Noskin, Lindsey E.; Paik, Hanjong; Tiwald, Thomas E.; Zheng, Qiye (2019-10-21). "Adsorption-controlled growth and properties of epitaxial SnO films". Physical Review Materials. 3 (10): 105202. Bibcode:2019PhRvM...3j5202M. doi:10.1103/PhysRevMaterials.3.105202. S2CID 208008118.
  15. ^ Moreno, M. S.; Varela, A.; Otero-Díaz, L. C. (1997). "Cation nonstoichiometry in tin-monoxide-phaseSn1−δOwith tweed microstructure". Physical Review B. 56 (9): 5186–5192. doi:10.1103/PhysRevB.56.5186.
  16. ^ Science and Technology of Chemiresistor Gas Sensors By Dinesh K. Aswal, Shiv K. Gupta (2006), Nova Publishers, ISBN 1-60021-514-9
  17. ^ "Red Glass Coloration - A Colorimetric and Structural Study" By Torun Bring. Pub. Vaxjo University.
  18. ^ Peplinski, D.R.; Wozniak, W.T.; Moser, J.B. (1980). "Spectral Studies of New Luminophors for Dental Porcelain" (PDF). Journal of Dental Research. Jdr.iadrjournals.org. 59 (9): 1501–1506. doi:10.1177/00220345800590090801. PMID 6931128. S2CID 20191368. Retrieved 2012-04-05.[permanent dead link]