Name the number of δs ‡ /cal mol −1 k −1 for butadiene being 1,2-dimethylene-cyclohexane
create table table_2068719_1 (δs_ varchar, _butadiene varchar, PRIMARY KEY (δs_))
select count(δs_) as ‡__cal_mol_−1_k_−1 from table_2068719_1 where _butadiene = "1,2-dimethylene-cyclohexane"