SnCl2 is ionic whereas SnCl4 is covalent why
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Who told you tin(II) chloride was ionic?
At room temperature, SnCl4 is a molecular liquid with a tetrahedral geometry, while SnCl2 consists of polymeric chains -[-ClSn(Cl)-]-, where each pyramidal Sn is connected to two bridging Cl atoms and one terminal Cl atom, and bears a lone pair. (Contrary to Brian B's answer, polymeric SnCl2 *does* have a complete octet at the tin centres.) But being a polymeric solid doesn't make it ionic. Even in the solid phase, SnCl2 does *not* consist of a repeating lattice of distinct Sn2+ cations and Cl- anions, which is what most people's definition of an ionic compound would require.
And in the gas phase, above 623ºC, SnCl2 goes monomeric as well, it's a discrete molecular species with a bent geometry. So there's no way you could justify calling that an ionic compound.
A crude approach to electronegativity, where you're just reading Pauling values off the periodic table, gives Sn at 1.96 and Cl at 3.16, so that's a difference of only 1.2. There are different formulas you can use to approximate the "ionic character" of a bond based on electronegativity differences, but Pauling's was (ionic percentage) = 1 – e^(–0.25*(delchi)^2), which gets you only 30 percent ionic character in those bonds. A slightly more sophisticated approach, where you admit that elements in different geometries and different canonical oxidation states ought really to be assigned different electronegativities, gets you a Pauling value of 1.80 for Sn(II), but even then you're only at 37 percent ionic, i.e. still more than three fifths covalent bonding. The differences are even smaller on the Mulliken scale.
Both the stannous and the stannic chlorides are primarily covalent bonding, neither consists of a lattice of discrete tin cations and chloride anions. Tin(II) chloride isn't an ionic compound.
Hope it helps you!!!
At room temperature, SnCl4 is a molecular liquid with a tetrahedral geometry, while SnCl2 consists of polymeric chains -[-ClSn(Cl)-]-, where each pyramidal Sn is connected to two bridging Cl atoms and one terminal Cl atom, and bears a lone pair. (Contrary to Brian B's answer, polymeric SnCl2 *does* have a complete octet at the tin centres.) But being a polymeric solid doesn't make it ionic. Even in the solid phase, SnCl2 does *not* consist of a repeating lattice of distinct Sn2+ cations and Cl- anions, which is what most people's definition of an ionic compound would require.
And in the gas phase, above 623ºC, SnCl2 goes monomeric as well, it's a discrete molecular species with a bent geometry. So there's no way you could justify calling that an ionic compound.
A crude approach to electronegativity, where you're just reading Pauling values off the periodic table, gives Sn at 1.96 and Cl at 3.16, so that's a difference of only 1.2. There are different formulas you can use to approximate the "ionic character" of a bond based on electronegativity differences, but Pauling's was (ionic percentage) = 1 – e^(–0.25*(delchi)^2), which gets you only 30 percent ionic character in those bonds. A slightly more sophisticated approach, where you admit that elements in different geometries and different canonical oxidation states ought really to be assigned different electronegativities, gets you a Pauling value of 1.80 for Sn(II), but even then you're only at 37 percent ionic, i.e. still more than three fifths covalent bonding. The differences are even smaller on the Mulliken scale.
Both the stannous and the stannic chlorides are primarily covalent bonding, neither consists of a lattice of discrete tin cations and chloride anions. Tin(II) chloride isn't an ionic compound.
Hope it helps you!!!
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