several elements exist as diatomic molecules
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Several elements exist as diatomic molecules
• Iodine is a solid of weakly-bonded diatomic molecules
• H2, N2, O2, F2, Cl2, Br2, I2
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Elements stack atoms to form solids in different ways.
Stacking Patterns:
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Solid elements display various forms called allotropes.
Carbon: diamond graphite buckminster fullerene
Phosphorus:
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https://www.webelements.com/compounds/iron/iron_sulphide.html
Sodium chloride consists of sodium cations and chloride anions stacked in a cubic arrangement.
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Calcium cations and phophate anions are bonded through ionic forces in calcium phosphate.
https://en.wikipedia.org/wiki/Dicalcium_phosphate
https://nutricorn-co.en.made-in-china.com/product/fMjnrdmCrZUF/China-High-Quality-Dicalcium-Phosphate-DCP-Mineral-Chemical-Products.html
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Lots of elements form oxides.
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Some oxides behave like acids, some like bases, and some can do both.
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https://www.webelements.com/compounds/iron/iron_sulphide.html
Iron (II) sulfide is a mineral called pyrite, which resembles gold.
https://www.amazon.com/Natural-Pyrite-Cube-Matrix-Beautiful/dp/B01MEF8PPC
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Silicon and oxygen bond covalently in multiple ways to create a variety of network solids.
• obsidian
• quartz
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Sucrose (table sugar) is a molecular solid.
https://crystallography365.wordpress.com/2014/01/12/sweet-crystallography-the-crystal-structure-of-sucrose/
https://en.wikipedia.org/wiki/Sucrose
• Molecules of sucrose are stacked in a crystalline structure, held together by weak forces
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• YBa2Cu3O7ceramic is superconducting at 77 K (just above liquid nitrogen’s boiling point).
• The ceramic structure is called perovskite
High temperature superconductors have a complex structure containing more than one metal.
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Metals with similar stacking patterns are more likely to form alloys.
Stacking Patterns:
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Two or more metals coexist in structures called alloys. Copper and tin mixed together form bronze.
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Effect of Carbon Content on the Properties of Steel
Carbon Content (%) Designation Properties Used to Make
0.05 - 0.19 Low Carbon Malleable, ductile Nails, cables
0.20 - 0.49 Medium Carbon High strength Construction girders
0.5 - 3.0 High Carbon Hard but brittle Cutting tools
Composition affects properties.