<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31457260</termId><termName>calcium carbonate</termName><termType>PT</termType><termNote><![CDATA[ A white crystalline powder occurring naturally chiefly as the minerals calcite and aragonite. ]]></termNote><termCreatedDate>2026-03-30 21:03:05</termCreatedDate><relation><relationType>UF</relationType><termId>31457261</termId><termName>carbonate, calcium</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31438463</termId><termName>calcium compounds</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31344616</termId><termName>aragonite</termName><termType>PT</termType></relation></term>  </Zthes>