<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31410862</termId><termName>iron sulfate</termName><termType>PT</termType><termNote><![CDATA[ A compound of iron and sulfate in which the ratio of iron (2+) to sulfate ions is 1:1. It is one of the main ingredients of iron-gall ink. ]]></termNote><termCreatedDate>2026-03-30 20:50:28</termCreatedDate><relation><relationType>UF</relationType><termId>31410863</termId><termName>ferrous salt</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31410864</termId><termName>ferrous sulfate</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31410865</termId><termName>iron (II) Sulfate</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31373704</termId><termName>sulfate</termName><termType>PT</termType></relation></term>  </Zthes>