Metasilicic acid is a hypothetical chemical compound with formula (HO)
₂SiO.^[1] The free acid slowly polymerises in aqueous solution even at low concentrations and cannot be isolated under normal conditions. Compounds including the conjugate base are known as metasilicates and occur widely in nature as inosilicates.

Metasilicic acid

Names
IUPAC name Metasilicic acid
Other names Silicic acid
Identifiers
CAS Number	7699-41-4 N
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL2068408
ChemSpider	14236 Y
ECHA InfoCard	100.028.834
EC Number	231-716-3
PubChem CID	14768
UNII	4OI8D3YOH1 N
CompTox Dashboard (EPA)	DTXSID30872499
InChI InChI=1S/H2O3Si/c1-4(2)3/h1-2H Y Key: IJKVHSBPTUYDLN-UHFFFAOYSA-N Y
SMILES O[Si](=O)O
Properties
Chemical formula	H2O3Si
Molar mass	78.098 g·mol−1
Conjugate base	Metasilicate
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H319, H335
Precautionary statements	P261, P264, P271, P280, P304+P340, P305+P351+P338, P312, P337+P313, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N (what is YN ?) Infobox references