Yingde Gases Group, a major mainland maker of industrial gases, saw its share price plunge 7.3 per cent to HK$6.45 yesterday. This came after it warned last Friday it expects to record an impairment loss on its 75 per cent stake in Zhangjiagang Yinde Gases, which makes fluoride, sulphur fluoride and nitrogen fluoride gases. Yingde said partner Smart Excel Investment which holds the remaining 25 per cent stake failed to provide the necessary know-how for cost-effective commercial production of the gases.