Related Experiment Video
Updated: Jun 27, 2026

Photochemical Oxidative Growth of Iridium Oxide Nanoparticles on CdSe@CdS Nanorods
Published on: February 11, 2016
Indium and iridium: Two rare metals with a high rate of contact sensitization
Isabella Terrani1, Kathrin Scherer Hofmeier2, Andreas J Bircher2,3
1Dermatology Unit, Ente Ospedaliero Cantonale Regional Hospital of Lugano, Lugano, Switzerland.
Background:
Humans are exposed to a variety of metals on a daily basis, and nickel is the most frequent contact allergen. Little is known about the frequency of sensitization to indium and iridium.
Objectives:
Study the prevalence of indium and iridium sensitization and evaluate the optimal patch test conditions.
Methods:
A total of 364 patients were patch tested at the allergy unit of the University Hospital of Basel. Pure metals, metal chlorides, and metal sulfates were applied in petrolatum or water in Inert Quadrate (IQ) test chambers for 2 days and read twice at day (D) 2, and between D4 and D7.
Results:
Eleven patients reacted to indium salts (3.0%), 13 to iridium salts (3.6%), and one reacted to both salts. None of the patients reacted to pure metals. Nineteen of the 23 patients who reacted either to indium or iridium showed concomitant positive reactions to other metals, mainly nickel and palladium.
Conclusion:
This retrospective clinical study provides insight into the prevalence and test conditions of two rarely tested metal allergens in a large patient cohort. A considerable number of indium- or iridium-positive subjects had co-sensitization to other metals.
Related Concept Videos
Periodic Classification of the Elements
Properties of Transition Metals
Metal-Ligand Bonds
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
Properties of Organometallic Compounds
The Periodic Table and Organismal Elements
Periodic Table Provides Information...
Metal-Semiconductor Junctions
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The semiconductor's...

