词条 | triad |
释义 | triad chemistry in chemistry, any of several sets of three chemically similar elements, the atomic weight of one of which is approximately equal to the mean of the atomic weights of the other two. Such triads—including chlorine-bromine-iodine, calcium-strontium-barium, and sulfur-selenium-tellurium—were noted by the German chemist J.W. Döbereiner between 1817 and 1829. The triad was the earliest atomic-weight classification of the elements. music ![]() Triads are classified according to intervals formed above the root. If the factors of the triad are a major third and a perfect fifth above the root, the triad is a major triad; if a minor third and a perfect fifth, it is a minor triad. These are defined as consonant triads. If the third is major and the fifth is augmented, the triad is called an augmented triad; if the third is minor and the fifth is diminished, the triad is a diminished triad. Augmented and diminished triads are dissonant. ![]() |
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