Declension table of ?tatvacāna

Neuter	Singular	Dual	Plural
Nominative	tatvacānam	tatvacāne	tatvacānāni
Vocative	tatvacāna	tatvacāne	tatvacānāni
Accusative	tatvacānam	tatvacāne	tatvacānāni
Instrumental	tatvacānena	tatvacānābhyām	tatvacānaiḥ
Dative	tatvacānāya	tatvacānābhyām	tatvacānebhyaḥ
Ablative	tatvacānāt	tatvacānābhyām	tatvacānebhyaḥ
Genitive	tatvacānasya	tatvacānayoḥ	tatvacānānām
Locative	tatvacāne	tatvacānayoḥ	tatvacāneṣu

Compound tatvacāna -

Adverb -tatvacānam -tatvacānāt