Clara Haber was born in Polkendorf near Breslau. Her father was a PhD chemist, inspiring Haber’s future education goals.
Haber began her education at a “Höhere Töchterschule” (“Women’s College”) in Breslau. In addition, she studied with a private tutor at home during the summer. Haber graduated from her college at 22 and then entered a teachers’ seminary.
At the time, teachers’ seminaries were the only types of institutions that allowed women to earn a high professional education. However, graduates were still only qualified for teaching at girls’ schools and were not allowed to study at a university. So, in order to qualify for university education, Haber took extensive private lessons to pass an exam that gave her a similar qualification as the Abitur. The Abitur is given to students in Germany, Lithuania, and Estonia who pass their final examinations after around 12-13 years of schooling. Haber ultimately passed the exam in 1896.
Haber then began her studies at the University of Breslau but only as a guest auditor. At the time, women weren’t legally admissible as university students. Prior to 1908, in order to attend lectures as guests, women were required to have both support from the professor and faculty and permission from the ministry of education. This approval process involved submitting a certificate of conduct and character references.
Haber was able to fulfill the requirements and conducted her PhD thesis under the supervision of Richard Abegg (1869-1910), a German chemist who is known as a pioneer of valence theory. Abegg proposed what we now know as Abegg’s law, which is the idea that the difference between the maximum positive and negative valence of elements often equals eight.
As mentioned above, Haber primarily focused on what is called solution chemistry. Solution chemistry centers around connections between solubility, the degree of dissociation, ion concentration, osmotic pressure, and electrochemical potential. In order to examine the relationships between these characteristics, Haber investigated cadmium, copper, lead, mercury, and zinc, as well as the salts of these elements. She was most interested in the idea of electroaffinity, which was proposed in 1899 by Abegg and his collaborator Guido Bodländer (1855-1904) as a new organizing principle in chemistry. Electroaffinity referred to the tendency of an atom or group of atoms in a molecule to form a negatively charged ion when the molecule is dissolved in a solvent.
Haber and Abegg’s paper expanded on Abegg and Bodländer’s ideas about electroaffinity, but Haber published two other solo papers that branched out topic-wise. In Haber’s thesis, she examined connections between the solubility of a selection of heavy metal salts, the concentrations of the ions formed when the salts were dissolved, and the potentials of the electrodes made from these metals when they were placed into a heavy-metal solution. Haber found that the ion concentrations ordered in accordance with the ions’ ellectroaffinities. She also found that the electroaffinities were additive, meaning that they were a property of each ion, not dependent on how each ion was bound to the others.
Haber’s second paper next centered on expanding the solubility database to include copper salts.
On a more personal note, Haber’s husband, Fritz Haber (1868-1934), was also a notable chemist. He played a key role in World War I and became known as the “father of chemical warfare” due to his role in weaponizing poisonous gases. Unfortunately, after marrying Fritz, Clara Haber found her own career dwindle.