Group 13 chemistry- Big Daddy Petr Flashcards
EX3 act as good LA/LB? Why?
LA as they possess a low energy p-orbital that can accept an EP to fill octet.
Group 13 compounds can form dimers to overcome lack of VE, what are these kinds of compounds called?
Electron deficient.
True/False, all group 13 form ionic compounds.
False B does not form ionic compounds.
True/False. all gp13 are non-metals
False only B is fully non-metal.
True/False, elemental boron is made of B12 icosahedra
True
Al is the second most important metal, give some properties.
Low density, high tensile strength, high EC, corrosion-resistant
Al(OH)3+OH- –>?
?–>Al(OH)3
Al(OH)3 +(conditions) –> Al2O3
How is Al obtained from Al2O3?
[Al(OH)4]-
conditions=1200C
Electrolysis with cryolite to lower mp to ca 1000C
B(OH)3 is a weak monobasic acid, however how does this differ to other oxoacids?
It acts as a LA
M3+ + aq –>?
? + H2O –> ??
? = [M(H2O)6]3+
??=[M(H2O)5(OH)]2+ + H3O+ (acidic)
True/False, both BH3 and BX3 dimerise. Why?
False BX3 is monomeric because X’s can donate towards empty p-orbitals on B, causing stabilisation.
AlCl3 is common as solid and is ionic nature, what about in l and g phase? What about for other halides? Why?
Forms dimers in l and g phase.
All other halides form dimers because Al has high LA, its also less efficient than B so prefers dimers.
BF3 is weaker than BI3 as a LA, why?
The back bonding means the 2p orbitals on the Boron are less electron deficient, so less able to receive an EP, this means they are weaker LA. Also, in CN 4, pi bonding is lost.
MX3 and M2X6 are examples of good what? Why are heavier examples even better?
LA.
Can exhibit hypervalency.
True/False All boron hydrides are flammable.
True
B2H6. How many electrons are there? What does this cause? What happens to the bond length?
12, this causes electron-deficiency.
The bond length increases compared to its terminal counterpart.
