<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31373729</termId><termName>potassium oxide</termName><termType>PT</termType><termNote><![CDATA[ A gray, crystalline mass that forms potassium hydroxide; it is soluble in water, alcohol, and ether. Toxic and corrosive to tissue, it used as a chemical reagent and intermediate. ]]></termNote><termCreatedDate>2026-03-30 20:40:47</termCreatedDate><relation><relationType>UF</relationType><termId>31373730</termId><termName>oxide, potassium</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31343456</termId><termName>potassium compounds</termName><termType>PT</termType></relation></term>  </Zthes>