Thymine Hydrogen bonding

[IreneSeo3F]

In the Marshmallow Final Review, #41D, can someone explain why thymine only forms 6 hydrogen bonds?

[Valerie Doan 3I]

I'm not sure what the Marshmallow problem is, but I counted 8 possible hydrogen bonds. Lone pairs of electronegative atoms, F, O, N, can act as hydrogen bond acceptors. Hydrogen atoms bonded to a F,O,N are hydrogen bond donors. With this in mind, you can see how many I found in the image. Someone correct me if I'm wrong because I don't have the problem :)

CNX_Chem_07_03_Impbioansd_img1.jpg (13.22 KiB) Viewed 272 times

[Anh Trinh 1J]

Valerie is right! Because there are 2 O atoms, 2 N atoms, and 2 H atoms, it can form 6 hydrogen bonds. (The picture is just for reference!)