常见符号及化学式的读法,化工学院 李 涛,一、常见符号的读法,+ pluspositive -minusnegative plus or minus,*be multiplied by times /be divided byover =equals (be equal to)is,greater than larger than less thansmaller than greater than or equal to,less than or equal to do not equal per,be approximately equal to be equivalent to be proportional to,yieldproduceresult in reacts inversely,lognX log X to the base n log10Xlog X to the base 10common logarithm logeXlog X to the base enatural logarithm,dxdifferential x;dee xdee of x dy/dxthe first derivative of y with respect to xthe n-th derivative of y with respect to x,y/uthe partial derivative of y with respect to u Xnthe nth power of xx to the power n X2x squarethe square of x X3x cubethe cube of x,y-10y to the minus tenth ( power ) degree Centigrade100 degrees Centigrade30 degrees below zero Centigrade degree Fahrenheit100 degrees Fahrenheit,常用希腊字母 alpha beta gamma delta epsilon eta theta mu nu xi rho upsilon lambda pi phi psi sigma omega zeta,二、化学分子式和方程式读法,化工科技人员在查阅文献时必然会遇到化学分子式和方程式。会认这些分子式和方程式并不难，但在一定特定场合需要用英文来读（或讲）这些分子式和方程式。 下面拟介绍在讲课和宣读论文时怎样用英文读化学分子式和方程式。（这里仅就一般情况加以介绍）。,凡英语字母，不论大小写都读英文字母名称的读音，如Aa读ei；Bb读bi:；Cc读si:等等。 凡数字般读one，two，three，four等。如K2SO4读成K-two-S-O-four。 但紧跟在圆括号后右下方的数目字则读成twice，three times，four times等。,符号的读法+ 读成plus-读成minus( )读成round brackets or brackets，,在化学分子式中遇到圆括号往往可不读，而把前后括号用pause表示； 也可把它的前括号读成open bracket(s)，后括号读成close bracket(s)； 或者在先读了括号里的符号后，再读in brackets。,例如(OH)2可有三种读法：pause-O-H-pause-twiceopen beacket-O-H-close bracket-twice-O-H-in bracket twice, 读成square brackets，若是络离子，例如Fe(CN)64可读成complexion，方括号可不读。,= 可读成equals或is equal to 在化学方应式中一般读成give(s)，yield(s)。AB+C 读成A gives B plus C。A+BC+D 读成A plus B gives C plus D或者读成A and B gives C and D。, 也可读成produce(s)，form(s)或become(s)。 例如：The reaction between A and B produces C。 读成reacts reversibly。,NaCO310H2O在等类似分子式中的中圆点，一般可读成dot。 例如上式可读成N-A-two-C-O-three-dot-ten-H-two-O。当然中间这一点也可不读，而以稍加停顿来表示。,在化学反应中可读成evolved as a gas或a gas is evolved，或gives off(a gas)。反应式中一般可读成X is precipitated 或X precipitates或gives an X precipitate。在分子式后注明其状态时，往往用（s）表示solid；(g)表示gas；(l)表示liquid。,在化学反应中，若用催化剂，如，同时又加热时，可读成：(1)in the presence of a Manganese dioxide as a catalyst on heating；(2)With a manganese dioxide catalyst under the influence of heat；(3)-M-N-O-two-catalyst-with-heat,上述为一般读法，但当口授听写时，必须表达清楚，大小写也宜读清。 Ca3(PO4)2通常情况下可读成C-A-three-pause-P-O-four-pause-twice；但当听写时，就应读成Capital C-small-A-three-open brackets-capital-P-capital-O-four-close branckets-twice。,