Water of crystallization degree of hydration can be critical to the resulting chemical properties. For example, anhydrous RhCl is not soluble in water and is relatively useless in organometallic chemistry whereas RhCl•3HO is versatile. Similarly, hydrated AlCl is a poor Lewis acid and thus inactive as a catalyst for Friedel-Crafts reactions. Samples of AlCl must therefore be protected from atmospheric moisture to preclude the formation of hydrates. Crystals of hydrated copper(II) sulfate consist of [Cu(HO)] centers linked to SO ions. Copper is surrounded by six oxygen atoms, provided by two different sulfate groups and four molecules of water. A fifth water resides elsewhere
Two Songs to be sung of a summer night on the water songs and other works by Delius with choral music by Arnold Bax. Two Songs to be sung of a summer night on the water Two Songs to be sung of a summer night on the water, Op. 91, were composed by Frederick Delius in 1917. He set the wordless works for choir a cappella. The songs were published in 1920 and first performed in 1921. Delius composed the songs at Grez-sur-Loing in 1917. He set them for six-part choir, SATTBB, without words, but vocalises on the syllable "uh". The first song is marked "slow but not dragging", the other which