1 | Undeniable Chemistry [S. Reid]

i. hydrogen

"PROFESSOR CRAWFORD?" She turns around to look down at one of her students, smiling softly in response. She puts down her papers on the desk, to give the student her full attention. "I had a question concerning this morning's lecture?"

"Yes, what can I do?" She asks her, making the girl blush slightly. The said student was a freshman, but Willow could see the potential she had. The first semester had come and gone, now nearing the end of the second semester, she looked forward to grading this student's paper, which she rarely would ever say.

"I don't think I understand how Halogen Bonds came to pass." The student admits, making Willow sigh softly as she sits down on her chair.

"Halogen Bonding was first discovered in the 1960s, so it's very recent. It is the attractive, non-covalent interaction that can form between an electrophilic region of a halogen atom in a molecule and a nucleophilic region of a molecule." Willow explains and she could see the wheels turning in the head of her student.

"Doesn't that just mean they form Ions and Covalent compounds?" The student asks, causing Willow to lean back and grin happily.

"Exactly. But don't forget it can only happen with Florine, Chlorine, Bromine and Iodine. And I just gave you the list in the order of strongest to weakest, can you tell me why that order?" Willow asks, making the student grin as she finally understands.

"Because the atomic size increases going down, meaning that Florine has a stronger hold on it's electrons than Iodine, which means Florine is less likely to share its electrons." The student says, making Willow nod appreciatively. "Thank you! I'll see you for tomorrow's lecture, Professor."

"Take care." Willow chuckles softly as the student runs off, making her shake her head in amusement. She doesn't get a moment to rest, when someone else walks into the office. Instead of a student, this time it is two men in suits. "Oh, good evening Gentlemen."

"Good evening, Professor." The taller one walks up to her desk, making her stand up and shake his hand. "I hope we're not bothering you."

"Oh, no it's fine." She smiles, nodding in acknowledgment to the other man. "Please take a seat."

"Thank you. I'm SSA Aaron Hotchner and this is my partner SSA David Rossi." He says as they sit down on the two seats in front of of her.

"FBI. What can I do for you?" She asks, making the two agents look at each other. Normally the BAU didn't involve outsiders in Classified investigations, but due to the gravity of this, they needed all hands on board.

"We have a chemical warfare that has been released in the open air in Annapolis." She takes in a deep breath, as he hands her a file with details of the case. "We would appreciate your help on this."

"I see. I've never dealt with anything like this. I'm not sure how helpful I can be." She admits, worry clearly painted over her features.

"We understand we are putting you in a difficult situation, but we wouldn't if it was necessary. You're a Professor in Chemistry, but you also graduated Medical School and studied Psychology, making you the perfect person for this." David Rossi says, making her bite her lip nervously.

"I'll come, but I can't promise I'll give you all the answers you need." She admits, making the three stand up.

"Thank you. We appreciate the effort. We'll have our team debrief you when you arrive in Annapolis." Aaron Hotchner says, making her smile.

"We look forward to working with you, Professor Crawford." SSA Rossi says, making her nod as she watches them leave her office, closing the door behind them. She drops into her chair with a deep sigh.

She understood how important this was, but she wasn't sure how helpful she was going to be.
With a deep breath, she dials a number on her phone and patiently waits as it rings. She balances her phone between her shoulder and ear, as she looks up the incident in Annapolis. Looking over the articles written by various sources, she huffs.

Still waiting for the Dean to answer the phone so she could announce her need to take a few days away, she ends up looking up the two agents she had just talked with. As she did so, she found out that Aaron Hotchner was in charge of the Behavioural Analysis Unit of the FBI and David Rossi was a known BAU agent who released a lot of books.