BondingIonic vs. CovalentMetallic BondsBond CharacterOther types of bondingIonic bondingSlide 7Slide 8Slide 9Bonding•Atoms come together in one of 3 principle types of bond–Ionic = + and - ions (charged atoms) joined by an electrostatic interaction–Covalent = Sharing of electrons equally between ions–Metallic – sharing of electrons between many atomsO2NaClIonic vs. Covalent•Elements on the right and top of the periodic table draw electrons strongly•Bonds between atoms from opposite ends more ionic, diatomics are 100% covalent•Bond strength Covalent>Ionic>metallic–Affects hardness, melting T, solubility•Bond type affects geometry of how ions are arranged–More ionic vs. covalent = higher symmetryMetallic Bonds•Electron sharing can go in any direction – results in more malleable material•Also affects electronic properties – metallic materials conduct electricity better•Affects redox reactions – where there is a transfer of electrons as a part of dissolution•electrons are nonbonding or delocalized, which makes materials less polar – and thus less soluble is waterBond CharacterOther types of bonding•Van der Waals – Interaction between molecular units which assemble a mineral from weak electrostatic interactions•Hydrogen – H+ bonds molecular subunits together•Dative – special type of covalent bond – all bonding electrons donated by one ionIonic bonding•Most common minerals on earth are composed of ionic bonds•Covalently bonded anionic subunits are often ionically bonded to cations to form these minerals – SiO44-, CO32-, PO43-, SO42-•Mineral properties are more often compared by the anionic component, thus most classification schemes focus on this.Ionic vs. CovalentBond strength Covalent>Ionic>metallic–Affects hardness, melting T, solubility•Bond type affects geometry of how ions are arranged–More ionic vs. covalent = higher symmetryIonic bonding•Most common minerals on earth are composed of ionic bonds•Covalently bonded anionic subunits are often ionically bonded to cations to form these minerals – SiO44-, CO32-, PO43-, SO42-•Mineral properties are more often compared by the anionic component, thus most classification schemes focus on this.Nesosilicates – SiO44-Sorosilicates– Si2O76-Cyclosilicates – Si6O1812-Inosilicates (single) – Si2O64-Inosilicates (double) – Si4O116-Phyllosilicates – Si2O52-Tectosilicates –
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