# Oxide content description

From time to time, I come by to see what people do with my mhchem package. Here, I came across a notation that I did not know yet: $\ce{K2O-nSiO2-xH2O}$ and $\ce{K2O - 3.2SiO2 - 2.7H2O}$

What is this? Is this really a bond? Is this a short form for writing $\ce{K2O-Si_nO_{2n}-H_{2x}O_x}$ and $\ce{K2O - Si_{3.2}O_{6.4} - H_{5.4}O_{2.7}}$? Is this an established notation that mhchem should support? (It doesn't yet with the numbers.) Do you have authoritative References?

• My gut feeling is that they should be hyphens. – Jan Oct 2 '17 at 11:56
• Dots, if anything. $\ce{K2O\cdot nSiO2}$... – Ivan Neretin Oct 2 '17 at 12:26
• I don't think this is standard notation, and the linked question suggests that it is rather a recipe or composition of a mixture of salts rather than an actual compound formula. – Martin - マーチン Oct 2 '17 at 12:28
• Wait, you're the author of mhchem?! – Zhe Oct 2 '17 at 12:59
• @IvanNeretin Dots make even more sense. I had thought the manufacturer had at least gotten the type of symbols right so my brain was stuck in the distinction between different types of horizontal lines ^^' – Jan Oct 3 '17 at 5:57