aMetantimonic(Chem) Pertaining to, or designating, an acid (formerly called antimonic acid) analogous to metaphosphoric acid, and obtained as a white amorphous insoluble substance, (HSbO3).
Century Dictionary and Cyclopedia
metantimonicNoting an acid, HSbO3, obtained by heating ortho-antimonic acid to 175° C. The metantimonic acid of Frémy (H4Sb2O7) is now called pyro-antimonic acid, thus preserving analogy with the different phosphoric acids.
Webster's Revised Unabridged Dictionary
Pref. met-, + antimonic,
Metantimonic acid, HSbO3, can be obtained by heating orthoantimonic acid to 175 deg.
"Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 2" by Various