I-Calcium hypophosphite, i-Ca(PH2O2)2: amakristalu angenalo umbala noma impuphu emhlophe enamakristalu, incibilika ezingxenyeni ezingaba ngu-6.5 zamanzi. Yenziwa ngokubilisa i-phosphorus nobisi lwekalishi (Procter, US Dispensatory 1907). Iyaqhuma uma igaywe noma ishiswe nama-nitrate, ama-chlorate noma ezinye ama-oxidiser.