Transition metal monoxides

Unless otherwise noted crystal structure is simple cubic like table salt NaCl.
Typical (with a few exceptions) is 1900°C melting point and Mohs 5.

Monometal monoxides

• ScO - no monoxide? (well its a rare earth anyway)

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• TiO - Titanium(II)_oxide - Hongquiite (webminera.com) - 4.96g/ccm | 5.36g/ccm(mineral) - Mohs 5 to 6 - 1,750°C
• VO - Vanadium(II)_oxide - no mineral - 5.758g/ccm - Mohs ?? - 1,789 °C
• CrO - Chromium(II)_oxide - no mineral - only powders by thermodynamic means - 300°C (low!) - Mohs ??
• MnO - Manganese(II)_oxide - Manganosite - 5.364g/ccm - Mohs 5 to 6 - 1,945 °C - water insoluble
• FeO - Iron(II)_oxide - Wüstite - 5.7g/ccm - Mohs 5.0 to 5.5 - 1,377°C - water insoluble
• CoO - Cobalt(II)_oxide - no mineral? - 6.45g/ccm - Mohs ?? - 1,933°C - water insoluble
• NiO - Nickel(II)_oxide - Bunsenite 6.898g/ccm - Mohs 5.5 - 1,955°C - watersolubility negligible

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• CuO - Copper(II)_oxide - tenorite 6.5g/ccm - Mohs 3.5 to 4.0 - 1,326 °C - water insoluble - Monoclinic
• ZnO - Zinc_oxide - [1] - 5.64–5.68g/ccm - Mohs 4 - 1,974°C (decomposes) - watersolubility minute - Hexagonal

Dimetal monoxides

• Cu₂O - Copper(I)_oxide - Cuprite - 6.14g/ccm - Mohs 3.5 to 4 - 1,232°C - water insoluble - cubic (but...)

There is more metal than oxygen but the material is still transparent. Odd.
Maybe because copper is pretty noble metal?

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More scarce silver (in the copper group below copper) does the same but the resulting material has much worse properties.

• Ag₂O - Silver_oxide - 7.14g/ccm - Mohs ?? - decompoes ≥ 200 °C - slightly water soluble - cubic (but...)

Related

• Binary gem-like compound
• (Classifications for gemstone like compounds)

External links

• Wikipedia Category:Transition_metal_oxides