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Names | |
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IUPAC name Tin(II) oxide | |
Other names Stannous oxide Tin monoxide | |
Identifiers | |
3D model (JSmol) | |
ChemSpider | |
ECHA InfoCard | 100.040.439 |
EC Number |
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PubChem CID | |
RTECS number |
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UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
SnO | |
Molar mass | 134.709 g·mol−1 |
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] |
insoluble | |
−19.0·10−6 cm3/mol | |
Structure | |
tetragonal | |
Thermochemistry | |
Std molar entropy (S⦵298) | 56 J·mol−1·K−1 [2] |
Std enthalpy of formation (ΔfH⦵298) | −285 kJ·mol−1 [2] |
Hazards | |
Flash point | Non-flammable |
NIOSH (US health exposure limits): | |
PEL (Permissible) | none [3] |
REL (Recommended) | TWA 2 mg/m3 [3] |
IDLH (Immediate danger) | N.D. [3] |
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 |
Tin dioxide | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
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.
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]
Tin(II) oxide burns in air with a dim green flame to form SnO2. [4]
When heated in an inert atmosphere initially disproportionation occurs giving Sn metal and Sn3O4 which further reacts to give SnO2 and Sn metal. [4]
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] 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]