contact ion-pairs
... that both solvent-shared and contact ion-pairs of magnesium and sulphate ions are present in sea-water?
... that both solvent-shared and <b id="mwErA"><a class="mw-redirect" href="./Ion-association" id="mwErE" rel="mw:WikiLink" title="Ion-association">contact ion-pairs</a></b> of <a href="./Magnesium" id="mwErI" rel="mw:WikiLink" title="Magnesium">magnesium</a> and <a class="mw-redirect" href="./Sulphate" id="mwErM" rel="mw:WikiLink" title="Sulphate">sulphate</a> ions are present in sea-water?