<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31343579</termId><termName>iridium</termName><termType>PT</termType><termNote><![CDATA[ Pure metallic element having symbol Ir and atomic number 77; a hard, brittle silvery-white metal of the platinum family. Iridium is the most corrosion-resistant metal and the second densest chemical element.  ]]></termNote><termCreatedDate>2026-03-30 20:32:39</termCreatedDate><relation><relationType>UF</relationType><termId>31343580</termId><termName>Ir</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31343581</termId><termName>osmiridium</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31343582</termId><termName>ruthenosmiridium</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31375243</termId><termName>nonferrous metal</termName><termType>PT</termType></relation><relation><relationType>BT</relationType><termId>31319740</termId><termName>elements</termName><termType>PT</termType></relation></term>  </Zthes>