Carbon forms an unusual unstable oxide of formula C3O2, called carbon suboxide. Carbon suboxide is made by using P2O5 to dehydrate the dicarboxylic acid called malonic acid, which has the formula HOOC-CH2-COOH.
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Average Bond Lengths for Some Single, Double and Triple Bonds
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Bond
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Bond Length(λ)
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Bond
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Bond Length(λ)
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C-C
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1.54
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N-N
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147
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C=C
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1-34
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N=N
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1.24
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C-C
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1.20
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N=N
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1.10
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C-N
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1.43
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N-0
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1.36
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CrerN
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1.38
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N=O
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1.22
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CrellN
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1.16
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0-0
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1.48
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C-0
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1.43
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0=0
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1.21
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C=0
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1.23
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C=0
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1.13
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(a) Write a balanced reaction for the production of carbon suboxide from malonic acid.
(b) How many grams of carbon suboxide could be made from 20.00 g of malonic acid?
(c) Suggest a Lewis structure for C3O2. (Hint: The Lewis structure of malonic acid suggests which atoms are connected to which.)
(d) By using the information in Table 8.5, predict the C-C and C-O bond lengths in C3O2.
(e) Sketch the Lewis structure of a product that could result by the addition of 2 mol of H2 to 1 mol of C3O2.