What type of isomerism is shown by pentaammine thiocyanate cobalt2?
Answers
in 1789 found a large amount of an oxide whieh resembled alumina
closely but ·differed from it in being insoluble in alkalies. It proved to be
the oxi~le of a n'ew metal t<;l which the name zirconium was applied from the min
!3ral zhcon, which name is probably a corruption of jargon, a Persian word,
IDel:ining gold-colored. Berzelhls studied the element and its compounds, which
he supposed were trivalent. He ·first, prepared the metal as an iron gray
powde!' in 1824 by reducing potassium fluQzirconate with potassium. ' In 1825
Berzel:i.us determined the atomic weight of zirconi llID. The crystalline metal
was first prepared by Troost in 1865. In 1857 Deville and Troost de~ermined
the vapor density of the chloride and established the quadrfvalence of the
element. The homogeneity of zirconia has been frequently questioned because
, of the complex mixtures in which the element is found in natUre, the diffi-
culty in the preparation of pure materials and t,he ease with which zirconitlJ!l
forms widely divergent basic compounds. In 1845 Svanberg reported the new
e3.r'th noria; in 1864 Nylander believed he had sel,arated two new oxides
from zirconia; in 1869 Sorby announced the discovery of jargonia and Church
found the new element nigriumj in 1901 Hofmann and Prandtl claimed to have
separated etlxener'de' froin the zirc'onia of euxeni teo Each of these announce-
ments has failed of confirmation. These numerous ex~eriences enhance the
scientific value of the discovery by Coster a,nd Revesy ;in 1923 of hafni urrl in
zirconium materiaL
The chemistry of the element has. d~ve1oped very slowly because previou