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Main trends in the development of methods for Main trends in the development of methods for the synthesis of phosphorus-containing macrocyclic com-the synthesis of phosphorus-containing macrocyclic compounds in the past 15 years are considered. Emphasis is pounds in the past 15 years are considered. Emphasis is given to reactions producing macrocyclic structures with the given to reactions producing macrocyclic structures with the participation of a phosphorus atom and other functional participation of a phosphorus atom and other functional groups involved in organophosphorus molecules and to groups involved in organophosphorus molecules and to modifications of macrocycles by phosphorus compounds modifications of macrocycles by phosphorus compounds in different valence states. Possibilities of the practical in different valence states. Possibilities of the practical application of phosphorus-containing macrocyclic com-application of phosphorus-containing macrocyclic compounds in difference areas of science and engineering are pounds in difference areas of science and engineering are discussed. The bibliography includes 205 references discussed. The bibliography includes 205 references. .

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I present high-resolution column density maps of two molecular clouds (MCs) having strikingly different star formation rates. To better understand the unusual, massive G216-2.5, an MC with no massive star formation, the distribution of its molecular gas is compared to that of the Rosette MC. Far-infrared data from Herschel are used to derive N(H 2 ) maps of each cloud and are combined with I CO data to determine the CO-to-H 2 ratio, X CO . In addition, the probability distribution functions (PDFs) and cumulative mass fractions of the clouds are compared. For G216-2.5, á ñ =Ń (H ) 7.8 10 2 20 cm −2 and á ñ =X 2.2 10 CO 20 cm −2 (K km s −1 ) −1 ; for the Rosette, á ñ =Ń (H ) 1.8 10 2 21 cm −2 and á ñ =X 2.8 10 CO 20 cm −2 (K km s −1 ) −1 . The PDFs of both clouds are lognormal for extinctions below ∼2 mag and both show departures from log-normality at high extinctions. Although it is the less-massive cloud, the Rosette has a higher fraction of its mass in the form of dense gas and contains  M 1389 of gas above the so-called extinction threshold for star formation, = A 7.3 V mag. The G216-2.5 cloud has  M 874of dense gas above this threshold.

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