Today in Science History – January 9 – Richard Abegg and Valence Theory

Richard Abegg
Richard Abegg (1869 – 1910)

January 9 is Richard Abegg’s birthday. Abegg was a German chemist who was one of the early researchers of valence theory. His experiments showed a tendency between the maximum and minimum valence levels of elements differed usually by a value of eight. This relationship became known as Abegg’s rule when Gilbert Lewis proposed his octet rules.

Abegg also discovered the principle behind freezing point depression of solvents. The freezing point is at the transition point between the liquid phase and the solid phase of a liquid. It is determined when the vapor pressures of the liquid and solid phases are equal. Abegg found if a solute was added to the solvent, the freezing point would be depressed to a lower temperature.

Abegg was also an avid enthusiast of ballooning. This hobby would ultimately cause his death when he flew his balloon with an engineer and female relative. When the balloon encountered strong winds, they opened the gas valves to cause the balloon to descend. The balloon managed to reach the ground safely and the other two were able to exit the basket. Abegg was caught as a gust of wind as he exited and was crushed by the basket.

Notable Science History Events for January 9

1998 – Kenichi Fukui died.

Fukui was a Japanese chemist who shares the 1981 Nobel Prize in Chemistry with Roald Hoffman for their independent research on the mechanics of chemical reactions. Fukui’s research centered on the outermost electron orbitals of a molecule and their change in shape when they bond during a reaction. He also investigated the reactions involving molecular nitrogen with transition metal complexes.

1950 – Alec Jeffreys was born.

Jeffreys is a British geneticist who developed the process of DNA fingerprinting. DNA fingerprinting, or DNA profiling is the technique used to assist identification of individuals based on their genetic makeup. It is used extensively in crime investigations and parental testing. Several countries now maintain DNA databases to assist in this work.

1922 – Har Gobind Khorana was born.

Khorana is an Indian-American biochemist who shares the 1968 Nobel Prize in Medicine with Robert W. Holley and Marshall Warren Nirenberg for their interpretation of the function of the genetics of protein synthesis. He discovered RNA spelled out a code of three-letter sequences for different amino acids to be produced. He was also the first to synthesize an oligonucleotide, or short nucleic acid polymers and the first to isolate DNA ligase.

1869 – Richard Abegg was born.

1848 – Caroline Lucretia Herschel died.

Caroline Lucretia Herschel
Caroline Lucretia Herschel (1750 – 1848)

Herschel was a German-Anglo astronomer and the sister of astronomer William Herschel. She assisted her brother with his observations and discovered three nebulae and several comets of her own. She was the first professional female astronomer.