c ry st all ine ▁pow der . ▁It ▁is ▁generated ▁industri ally ▁in ▁the ▁production ▁of ▁met all ic ▁iron . ▁ ▁Pre par ation ▁and ▁general ▁properties ▁M g S ▁is ▁formed ▁by ▁the ▁reaction ▁of ▁sul fur ▁or ▁hydro gen ▁sul f ide ▁with ▁mag nes ium . ▁ ▁It ▁cry st all izes ▁in ▁the ▁rock ▁salt ▁structure ▁as ▁its ▁most ▁stable ▁phase , ▁its ▁z inc ▁bl ende ▁and ▁wur tz ite ▁structures ▁can ▁be ▁prepared ▁by ▁mole cular ▁beam ▁ep it axy . ▁The ▁chemical ▁properties ▁of ▁M g S ▁res emble ▁those ▁of ▁related ▁ion ic ▁sul f ides ▁such ▁as ▁those ▁of ▁sod ium , ▁b arium , ▁or ▁calci um . ▁It ▁react s ▁with ▁o xygen ▁to ▁form ▁the ▁corresponding ▁sul f ate , ▁mag nes ium ▁sul f ate . ▁ ▁M g S ▁react s ▁with ▁water ▁to ▁give ▁hydro gen ▁sul f ide ▁and ▁mag nes ium ▁hydro x ide . ▁ ▁App lications ▁In ▁the ▁B OS ▁ste elm aking ▁process , ▁sul fur ▁is ▁the ▁first ▁element ▁to ▁be ▁removed . ▁Sul fur ▁is ▁removed ▁from ▁the ▁imp ure ▁bl ast ▁furn ace ▁iron ▁by ▁the ▁addition ▁of ▁several ▁hundred ▁kil og rams ▁of ▁mag nes ium ▁pow der ▁by ▁a ▁lance . ▁Mag nes ium ▁sul f ide ▁is ▁formed , ▁which ▁then ▁flo ats ▁on ▁the ▁mol ten ▁iron ▁and ▁is ▁removed . ▁ ▁M g S ▁is ▁a ▁wide ▁band - g ap ▁direct ▁sem