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Pekka Pyykkö

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Pekka Pyykkö in 1991

Veli Pekka Pyykkö (born 12 October 1941)[1] is a Finnish academic. He was professor of Chemistry at the University of Helsinki.[1] 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,[2][3] known as the Pyykkö model.[4]

Pyykkö has also studied the relativistic effects present in heavy atoms and their effects in NMR.[5]

Pyykkö model

[edit]

After the 118 elements now known, 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.[6]

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.[6]
Pyykkö model
Pyykkö-displaced elements are in boldface
 8  119
Uue
120
Ubn
121
Ubu
122
Ubb
123
Ubt
124
Ubq
125
Ubp
126
Ubh
127
Ubs
128
Ubo
129
Ube
130
Utn
131
Utu
132
Utb
133
Utt
134
Utq
135
Utp
136
Uth
137
Uts
138
Uto
141
Uqu
142
Uqb
143
Uqt
144
Uqq
145
Uqp
146
Uqh
147
Uqs
148
Uqo
149
Uqe
150
Upn
151
Upu
152
Upb
153
Upt
154
Upq
155
Upp
156
Uph
157
Ups
158
Upo
159
Upe
160
Uhn
161
Uhu
162
Uhb
163
Uht
164
Uhq
139
Ute
140
Uqn
169
Uhe
170
Usn
171
Usu
172
Usb
9 165
Uhp
166
Uhh
167
Uhs
168
Uho
  s-block g-block f-block d-block p-block

The compact version:[6]

Extended periodic table. P. Pyykkö, PCCP 2011, 13, 161. @RSC. Reprinted with permission.
Extended periodic table. P. Pyykkö, PCCP 2011, 13, 161. @RSC. Reprinted with permission.

Pekka Pyykkö correctly predicted the existence of chemical bonds between gold and the noble gas xenon, which is usually inert; this bond is known to occur in the cationic complex tetraxenonogold(II) (AuXe2+
4
). He also correctly predicted the existence of gold–carbon triple bonds.[7]

References

[edit]
  1. ^ a b "Curriculum vitae". chem.helsinki.fi. 2012-04-25. Archived from the original on 2012-02-19. Retrieved 2012-05-28.
  2. ^ Roberts, Siobhan (27 August 2019). "Is It Time to Upend the Periodic Table?". The New York Times. Retrieved 7 December 2019.
  3. ^ Kean, Sam (30 January 2019). "A storied Russian lab is trying to push the periodic table past its limits—and uncover exotic new elements". Science. Retrieved 7 December 2019.
  4. ^ Atsumi, Michiko (2013). "SCCJ Cafe -Season 3-Theoretical Chemistry in Nordic (2)"The Extended Periodic Table − Pyykkö Model"". Journal of Computer Chemistry, Japan. 12 (2): A18–A20. doi:10.2477/jccj.2013-0008.
  5. ^ Vaara, Juha; Pyykkö, Pekka (2003-02-15). "Relativistic, nearly basis-set-limit nuclear magnetic shielding constants of the rare gases He–Rn: A way to absolute nuclear magnetic resonance shielding scales". The Journal of Chemical Physics. 118 (7): 2973–2976. doi:10.1063/1.1545718. ISSN 0021-9606.
  6. ^ a b c Pyykkö, Pekka (2011). "A suggested periodic table up to Z≤ 172, based on Dirac–Fock calculations on atoms and ions". Physical Chemistry Chemical Physics. 13 (1): 161–8. Bibcode:2011PCCP...13..161P. doi:10.1039/c0cp01575j. PMID 20967377. S2CID 31590563.
  7. ^ Scientific American June 2013, "Cracks in the Periodic Table". p. 72.