Pekka Pyykkö

Veli Pekka Pyykkö (born October 12, 1941) is a Finnish academic. He is professor of Chemistry at the University of Helsinki. From 2009–2012, he was the chairman of the International Academy of Quantum Molecular Science. He is known for his extension to the periodic table of elements, known as the Pyykkö model.

Pekka Pyykkö predicts that the orbital shells will fill up in this order:

• 8s,
• 5g,
• the first two spaces of 8p,
• 6f,
• 7d,
• 9s,
• the first two spaces of 9p,
• the rest of 8p.

He also suggests that period 8 be split into three parts:

• 8a, containing 8s,
• 8b, containing the first two elements of 8p,
• 8c, containing 7d and the rest of 8p.

The compact version:

Pekka Pyykkö successfully predicted the possibility of a chemical bond between gold and the noble gas xenon, which is usually inert; this bond is known to occur in the cationic complex tetraxenonogold(II) (AuXe
₄). He also successfully predicted the possibility of a gold–carbon triple bond.